Hmmm...
I periodically get the "Please Log in Again"... or something to that effect, when I'm obviously logged in. It usually has to do with my not quite finishing a reply, and either sleeping on it, or forgetting it for a while, finding it again, and finishing writing.
Sometimes I can get it back with a back button or refresh. I think it depends on what screen I was on. I think Quick Reply normally eats my messages.
Fortunately, it has been a while since that has popped up.
I do periodically get time-outs when replying. I scramble to copy anything I can, and save it on my machine if possible. I think Bike Forums does usually allow a "reload".
I am more likely to lose something that I wrote on my cell phone than on the laptop, and I think it is due to the phone.
And, of course, in general, my slow internet connection doesn't help.
I suppose I've gotten used to a few of BF's quirks.
The worst thing is that everybody knows that newbies have issues with posting photos. Yet, it is just that way by design.