Updated to latest version.
Pi-hole version is v5.5 (Latest: v5.5)
AdminLTE version is v5.7 (Latest: v5.7)
FTL version is v5.10.2 (Latest: v5.10.2)
Lately I suspected Pihole is not blocking anymore.
Followed Example 4 from the docs.
Flushed caches AFAIK.
On the whitelist:
These domains are only member of 'Socials' group
Client not member of 'Socials' group.
Client is member of 'Default' group.
Block domain when domain only member of added group and client not member of that group.
domain is resolved.