I have the same issue in one photography forum. I was told it's THEIR issue with they way they have something configured in their software (it/ a huge forum). I have no problems here nor do I with other forums. However, the one that is terribly laggy makes me want to not post. Maybe a good thing LOL
To be 100% honest.
I was on my iPad last night, and I was typing a post to this forum.
I had quite terrible keyboard stickyness/delays in typing in.
Sometimes, I typed say 3 or 4 character and nothing happened, not even any click sound, and then all 3 or 4 characters appeared on screen at once.
I was only 1 or 2 finger typing as well, so not very quick. Perhaps there is some video/advert on these forums that's slowing down the keyboard input?
1st time I'd experienced it, and to be honest, if I was a fast typer it would of been unusable.