I always just assumed it was my internet connection... Meh. Inconvenient, yes, but not worth getting my knickers in a twist about. (Though it is irritating when it deletes allllll that stuff I /just/ spent my valuable time typing out.... >_<)
I had too, until I asked this and suddenly everyone else was having problems. I'm not that upset about it necessarily. I just hate retyping stuff, especially some of my really long messages (which usually means whoever I was talking to doesn't get a message back for another month) or deleting a huge bucketload of deviation messages from the groups I'm part of (which can get up to 100+ deviations) and suddenly it says 'Error: Messages Cannot Be Deleted at This Time' and all those messages are right back where they started and I don't remember what I'd deleted.