<Retail> Several characters have had their ilv reduced from 545 to 408

I have three characters mostly affected. Two had an average item level of 546 back in March, if not the beginning of April - my favourite one now has an average of 382 without swapping a single piece of gear - I spent a fair few bob in getting the gear across five characters (lets say, seven figures) yet I can still see the type of gear in the Auction House - so I have no clue what has happened. I submitted a bug, and I first noticed it when a friend asked for help. I was phased, so he party synced, and it feels like I haven’t been unsynced since.

Wondering if any other land and sea dwellers have experienced the same thing?