SUMMARY
***
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file:
https://bugs.kde.org/....
some text
https://bugs.kde.org/....
some text
https://bugs.kde.org/...
some text
https://portugalforum.org/

STEPS TO REPRODUCE
1. crtl r from https.*\n (all lines are marked) replace with : nothing
2. many lines are markes and selecting replace all (Alle ersetzen) replaces only one line
3. repeating "replace all" replaces the next line... like pressing "replace" alone.

OBSERVED RESULT 
replace all replaces only one off the marked lines.
repeating replace all only the next marked line is replaced.
Search and replace from the extern module (able to replace in all files) works as expected, there selecting "actual file" is now my workaround. 
(if lines are for example like https://bugs.kde.org/.../text.txt
the regex: "https:.*\.txt\n" all lines are marked, it's the same as ".*\n" -> replace all replaces only one line
the external replace module has no problems

hope I named the english buttons correctly 
                german                 english
button:  "Ersetzen"        -> "replace"
button   "Alle ersetzen" -> "replace all"


EXPECTED RESULT
replace all should replace all marked lines (as in earlier versions)

SOFTWARE/OS VERSIONS
Betriebssystem: openSUSE Leap 15.4
KDE-Plasma-Version: 5.24.4
KDE-Frameworks-Version: 5.90.0
Qt-Version: 5.15.2
Kernel-Version: 5.14.21-150400.24.18-default (64-bit)

Grafik-Plattform: X11
Prozessoren: 12 × AMD Ryzen 5 2600 Six-Core Processor
Speicher: 15,5 GiB Arbeitsspeicher
Grafikprozessor: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2