The increase/decrease rep bug afflicts all races and seems to be random. It is a known bug since at least 11.0 went live.
FWIW I’ve only seen actual rep issues on humans.
All the rest are UI bugs not actual rep gain bugs. That I have experienced at least.
That’s when I check using addons or other in-game menus I can see the correct rep.
Humans though, their gains for some factions are askew due to the removal of their rep gain perk.
If it’s others, not UI bugs and not humans, oof. I have not experienced that. And I hope I do not! With the guild bank bug and others I’m tapped out.