HI @LeePublic did your post have many numbers?
Sometimes that could make the system think it is a credit card or some personal info
Check if you see the post here:
Beside breaking any rule other members had pointes out, the following behavior are normal just in case you don't know. You can recover the autosaved post by replying to same post again.
1. Refresh before autosave: Get warning message
2. Refresh after autosave: Post disappear without any warning
3. Reply to the same post again, get this message.