I think #2 happen because when you logged in using HiveSigner, the token is valid only for a set amount of days. When you press "Submit", your content cannot get published onto the blockchain.
I could replicate error #3. I will now try to replicate error #4
I think your theory is accurate. If that is the case, there would be roughly 5% polls on dPoll.io that could not be posted on the blockchain and cannot be answered nor deleted. That is until fixes are made.