There have been occasional reports of character corruption for many months. In these situations the affected character losses one or more of the following:
1) Inventory items
2) Learned recipes
3) Items out of the wallet - green - account shared items are what I remember reading
4) Active quest log - all quests are cancelled.
5) Stuff in the stoage like housing chests - vault - shared storage - wardrobe
6) A number of other can not explain losses.
My personal opinion there is something wrong in the character load and save functionality. Or perhaps the character data itself got messed up and the auto repair functionality fixed it by deleting everything in the corrupted part of the character data. Since all character live on an account, there is always possibility that it is an account level corruption which results in the removal of all data for every character on the account for the specific area.
Over the yearsworking in software development, I've had to investigate a lot of database degradation issues in real time systems. It is a big problem for persistent systems like telecommunications, banking, social security and games. Games are developed on shoe strings, baling wire and bubble gum. Every game I've played has data corruption and loss issues. You hope you are not the customer singled out for torment. Or if you are affected the issue is easy to recover from. Or the game operator will compensate for your loss.
Unless stated otherwise, all content in this post is My Personal Opinion.