Default language not applied in multi user Plex

[mgutt]

Solved this issue:

Selected default language is ignored if Plex is installed manually

It took a while, but now I found the source of the default language problem. There are multiple threads covering this problem: Language selection changed but ignored Default language not applied in multi user Plex PMP playing movies in wrong language despite language preferences Default language! (Bug?) Wrong default audio language despite correct profile setting (web player, all apps) As it happend for me much later than for the users in these threads I asked myself what I changed in the las…