I have completed the storylines for all orc strongholds including the one for Malacath, Borgakh the Steel Heart was even my companion for a few quests.
Suddenly the orcs in Mor Khazgur can't remember me. When I visited the loghouse everybody called me outlander and told me to get out. I could not even ask Borgakh to follow me as a companion. There was no conversation option with anyone.

I initially thought that maybe it was because of Serena sollowing me. I parted ways with her but things did not improve. I can live without Borghak but if this tehdency spreads among other factions, this may cause problem.

Any suggestions? Any mod that might cause this?

What mods do you have?

Can't you use console commands to raise your "friendship" level with them?