About a month ago Honor level on my account was reset to 1 when I was about to reach level 80. I didn’t receive any warnings or emails and I didn’t PVP for quite a while (besides farming Tol Barad and occasional skirmishes). So I noticed it only when my Honor level icon changed after playing on US Starter account (WOW1) and a bug which reset my UI, macros and key bindings. That was probably because US WOW1 and EU WOW1 share same WTF account directory.
I couldn’t resolve this issue with support team. In the first ticket GM misunderstood the problem, and another GM referred to restrictive measures taken against the account in the past, which were of a completely different nature and were successfully challenged by me. In the second ticket GM couldn’t help either. And in the third they suggested I just grind it all back.
UPD So CS acknowledged it was a bug and suggested I make a bug report which I did ingame.
UPD Fixed with patch 11.1.0 (or 11.1.5).