Nextcloud behind squid

Face Strange behaviour of Nextcloud behind Squid Proxy (pfsense).
Every second time (not every time) I reload i get “Untrusted Domains” error.

I have another Nextcloud installation behind the same proxy without any problems at all.
Trusted domains configured in config.php

I am working on that all day with no result and Im pissed now (sry). Either I find a solution very soon or i never again will use nextcloud.