SUMMARY
if initial directory on startup is not available, dolphin freezes. 

STEPS TO REPRODUCE
1. Set startup folder to "Last time"
2. Navigate to remote mounted directory
3. Quit dolphin
4. Stop remote filesystem connection
5. Restart Dolphin

OBSERVED RESULT
Displays a window frame, then freezes. Not good if system is restoring windows after a reboot. 

EXPECTED RESULT
Normal app start, possibly defaulting to an available folder (eg ~ or root). 

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: kde-plasma/plasma-desktop-5.20.5-r1:5

(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: KDE Frameworks 5.77.0
Qt Version: Qt 5.15.2 (built against 5.15.2)

ADDITIONAL INFORMATION
Dolphin version 20.08.3

uname -a: Linux bartali 5.10.27-gentoo #1 SMP Sat Apr 3 10:00:22 CDT 2021 x86_64 AMD Ryzen 5 3600 6-Core Processor AuthenticAMD GNU/Linux

Gentoo emerge --info: 
jesnow@bartali ~ $ emerge --info
Portage 3.0.17 (python 3.8.8-final-0, default/linux/amd64/17.1/hardened, gcc-10.2.0, glibc-2.32-r7, 5.10.27-gentoo x86_64)
=================================================================
System uname: Linux-5.10.27-gentoo-x86_64-AMD_Ryzen_5_3600_6-Core_Processor-with-glibc2.2.5
KiB Mem:    16317452 total,  12065828 free
KiB Swap:   22330364 total,  22330364 free
Timestamp of repository gentoo: Sat, 03 Apr 2021 21:00:01 +0000
Head commit of repository gentoo: 4569c4a5fd706b1b4ae70fcc4b78a3c7f29a27e1
Head commit of repository TDE: 3c9039ff82ddb2c8d7b21ade4006cfd898bac3cd

Head commit of repository abendbrot: 5835bdd21ddccdfe1dfea8e2b0a77690dfad4b81

Timestamp of repository audio-overlay: Wed, 31 Mar 2021 12:54:54 +0000
Head commit of repository audio-overlay: 7c7897a3dc5430483112b36df7566bb899c98213

Head commit of repository cloveros: fd7a52022d156499d1dc2b9e6f626a65de5e875e

Head commit of repository compiz-reloaded: b866d7c11266e31485fb3827d44e2491f6e7d734

Head commit of repository tlp: ced908095a1bafc1af3583efc4a24b39e2ab8c12

sh bash 5.0_p18
ld GNU ld (Gentoo 2.35.1 p2) 2.35.1
distcc 3.3.3 x86_64-pc-linux-gnu [enabled]
ccache version 4.2 [enabled]
app-shells/bash:          5.0_p18::gentoo
dev-java/java-config:     2.3.1::gentoo
dev-lang/perl:            5.30.3::gentoo
dev-lang/python:          2.7.18_p7::gentoo, 3.7.10::gentoo, 3.8.8::gentoo, 3.9.2::gentoo
dev-util/ccache:          4.2::gentoo
dev-util/cmake:           3.18.5::gentoo
dev-util/pkgconfig:       0.29.2::gentoo
sys-apps/baselayout:      2.7::gentoo
sys-apps/openrc:          0.42.1-r1::gentoo
sys-apps/sandbox:         2.20::gentoo
sys-devel/autoconf:       2.13-r1::gentoo, 2.69-r5::gentoo
sys-devel/automake:       1.13.4-r2::gentoo, 1.16.2-r1::gentoo
sys-devel/binutils:       2.35.1-r1::gentoo
sys-devel/gcc:            10.2.0-r5::gentoo
sys-devel/gcc-config:     2.3.3::gentoo
sys-devel/libtool:        2.4.6-r6::gentoo
sys-devel/make:           4.3::gentoo
sys-kernel/linux-headers: 5.10::gentoo (virtual/os-headers)
sys-libs/glibc:           2.32-r7::gentoo
Repositories:

gentoo
    location: /var/db/repos/gentoo
    sync-type: rsync
    sync-uri: rsync://merckx/gentoo-portage/
    priority: -1000
    sync-rsync-verify-max-age: 24
    sync-rsync-verify-metamanifest: yes
    sync-rsync-extra-opts: 
    sync-rsync-verify-jobs: 1

TDE
    location: /var/db/repos/TDE
    sync-type: git
    sync-uri: https://github.com/ormorph/TDE
    masters: gentoo

abendbrot
    location: /var/db/repos/abendbrot
    sync-type: git
    sync-uri: https://github.com/barbudreadmon/abendbrot.git
    masters: gentoo

audio-overlay
    location: /var/db/repos/audio-overlay
    sync-type: git
    sync-uri: https://github.com/gentoo-mirror/audio-overlay.git
    masters: gentoo

cloveros
    location: /var/db/repos/cloveros
    sync-type: git
    sync-uri: https://gitgud.io/cloveros/cloveros-overlay.git
    masters: gentoo

compiz-reloaded
    location: /var/db/repos/compiz-reloaded
    sync-type: git
    sync-uri: https://github.com/ethus3h/compiz-reloaded-overlay.git
    masters: gentoo

tlp
    location: /var/db/repos/tlp
    sync-type: git
    sync-uri: https://github.com/dywisor/tlp-portage.git
    masters: gentoo

ACCEPT_KEYWORDS="amd64"
ACCEPT_LICENSE="*"
CBUILD="x86_64-pc-linux-gnu"
CFLAGS="-O2 -pipe"
CHOST="x86_64-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/lib64/libreoffice/program/sofficerc /usr/share/config /usr/share/gnupg/qualified.txt"
CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/dconf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo"
CXXFLAGS="-march=x86-64 -mtune=generic -O2 -pipe"
DISTDIR="/var/cache/distfiles"
ENV_UNSET="CARGO_HOME DBUS_SESSION_BUS_ADDRESS DISPLAY GOBIN GOPATH PERL5LIB PERL5OPT PERLPREFIX PERL_CORE PERL_MB_OPT PERL_MM_OPT XAUTHORITY XDG_CACHE_HOME XDG_CONFIG_HOME XDG_DATA_HOME XDG_RUNTIME_DIR"
FCFLAGS="-march=x86-64 -mtune=generic -O2 -pipe"
FEATURES="assume-digests binpkg-docompress binpkg-dostrip binpkg-logs ccache config-protect-if-modified distcc distlocks ebuild-locks fixlafiles ipc-sandbox merge-sync multilib-strict network-sandbox news parallel-fetch pid-sandbox preserve-libs protect-owned qa-unresolved-soname-deps sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync xattr"
FFLAGS="-march=x86-64 -mtune=generic -O2 -pipe"
GENTOO_MIRRORS="http://distfiles.gentoo.org"
LANG="en_US.utf8"
LDFLAGS="-Wl,-O1 -Wl,--as-needed"
MAKEOPTS="-j12"
PKGDIR="/var/cache/binpkgs"
PORTAGE_CONFIGROOT="/"
PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --omit-dir-times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --exclude=/.git"
PORTAGE_TMPDIR="/var/tmp"
USE="X \ acl aio alsa amd64 bindist bzip2 cli crypt cups dga dri dri3 egl elogind exif fftw gif graphite hardened iconv ipv6 jack jit joystick jpeg lcms libglvnd libtirpc minimal multilib ncurses nptl numa offensive opencl openexr opengl openmp openssl otr pam pcre pie png policykit pulseaudio qt5 raw readline samba seccomp split-usr ssl ssp system-av1 system-binutils system-cairo system-clang system-cmark system-compress system-digest system-ffmpeg system-harfbuzz system-heimdal system-icu system-images system-jpeg system-lcms system-leveldb system-libevent system-libmspack system-libs system-libvpx system-libyaml system-llvm system-lua system-lz4 system-nss system-openjpeg system-pixman system-renpy system-snappy system-sqlite system-tbb system-uulib system-vpx system-zlib threads unicode v4l2 vaapi vdpau vulkan win32codecs xattr xinerama xorg xtpax zlib zsh-completion" ABI_X86="64" ADA_TARGET="gnat_2018" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" APACHE2_MODULES="authn_core authz_core socache_shmcb unixd actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias" CALLIGRA_FEATURES="karbon sheets words" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" CPU_FLAGS_X86="aes avx avx2 f16c fma3 mmx mmxext pclmul popcnt sha sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock greis isync itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf skytraq superstar2 timing tsip tripmate tnt ublox ubx" INPUT_DEVICES="libinput" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" LLVM_TARGETS="NVPTX X86" LUA_SINGLE_TARGET="lua5-1" LUA_TARGETS="lua5-1" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php7-3 php7-4" POSTGRES_TARGETS="postgres10 postgres11" PYTHON_SINGLE_TARGET="python3_8" PYTHON_TARGETS="python3_8" RUBY_TARGETS="ruby26" USERLAND="GNU" VIDEO_CARDS="nvidia" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq proto steal rawnat logmark ipmark dhcpmac delude chaos account"
Unset:  CC, CPPFLAGS, CTARGET, CXX, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LC_ALL, LINGUAS, PORTAGE_BINHOST, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS