Apparently some replies to topics have been disappearing recently.
This forum is running on bbPress. I don’t know why this has been happening, but bbPress just released a new version within the past few days, and we’ver upgraded to the new version.
I hope this will cure that issue, but it is possible that because of all the new WordPress changes, and versions of PHP that some of the support plugs we use for this forum may be causing the problem.
In the mean time, be sure your reply shows up after you post. It does seem that trying again can eventually get your post there, so if you have difficulties, copy your post so you can simply paste it on the retry.
Sorry – bbPress is widely used, and seems very reliable.