Well, I have roughly the same problem as this post, but high contrast mode is disabled. Since yesterdays (20220531) update an array of apps (settings, extensions, calendar, nautilus etc) does not seem to adopt the configured window theme anymore. Does anyone have a clue what this is about?
Welcome to the forum! 
See:
Thank you! I just learned about the libadwaita implementation and all its consequences on theming…
Cheers,
Stan