1) Did you do multiple edits? The forum doesn’t like it if you do multiple edits back to back. It has a response function that will remove your post.
2) Did you have a lot if images or videos in it? After a certain point, a post will nuke itself when you submit it if there are too many link, images, or videos in it.
It’s annoying, and the admins need to fix it, and we’ve been asking for these things for months, but considering this is a homebrew website not a cookie cutter they are slow to make the changes. Once you know how to maneuver around the forum quirks it’s workable.