I have users complaining about this using xf 1.3.5
It has also happened to me a couple of times, at post creation. For me it seemes to happen when I write a post that is to become top of next page, post #21 or #101 as an example.
The only way I could see this happening is if the draft save request fires before the reply button is clicked but actually saves itself after the reply. In this case, I don't think we can really do anything. Once the draft save has been sent, we can't really stop it. I would normally say that this should be rather unlikely; the reply process should be much more time consuming that the draft save request. (Previously, the draft could be written unexpectedly if the draft save request fired while waiting for the reply request to come back; that is what was prevented in the other bug report.)
I can't see any other way for this to occur unless there's some broken JS. Can you confirm it here? Can you confirm it with add-ons disabled while using the default style? Can anyone else confirm this?
Some of my users says it happens to them most every day, but not all the time. As it doesn’t happen that often to me, it would be very difficult to turn of all add-ons and use default style, unfortunately.
It can be broken JS or an add-on, is there any way to try to figure it out without turning them all off?
This seems really odd, I've never had it happen. Granted I don't post that much but I post enough to where I feel I would have encountered this if it was that common. In theory it seems like something that would take incredible timing. Maybe you do have an add on that is affecting it although I'm not sure how that would happen. Maybe if you could post a list of your add ons?