The "Denmark - English (en_DK)" locale presents clock in a weird/unexpected form. Most locales use ":" as separator but en_DK uses "." for unknown reason. STEPS TO REPRODUCE 0. install locales for en_DK.UTF-8 1. Open Formats system settings module 2. select "Denmark - English (en_DK)" for the "Time" 3. check the output under examples 4. compare it with the output of LC_TIME=en_DK.UTF-8 date +"%x %X" OBSERVED RESULT Time separator is "." like in "11.19.03" or "11.19" EXPECTED RESULT Time separator is ":" as in the libc locale. Like "11:19:03" or "11:19" SOFTWARE/OS VERSIONS See what is shipped in Debian stretch (or Debian buster on 2018-12-10)
Locale handling is done by the Qt frameworks. If this is reproducible with Qt 5.11 or newer, please report this issue to Qt developers via https://bugreports.qt.io/ Please note that en_DK is not an offical (ISO supported) locale, but a hack for the limited POSIX locale system. Qt does not use the POSIX database, but the CLDR database.