I noticed something recently regarding the draft but I will like ask if the draft has a specific save to draft interval or all we have to do is click on the preview button everytime we need to save to draft.
I don't say I know everything about draft feature of the forum, but I can help you some information.
Draft page - Pros & Cons.My advice to you, don't rely on forum draft feature and if you are composing your posts, do it with text composing software, app and save your drafts with them. When you feel you finish your post content, copy and past it here for posting.