Yes, I think it can. The current situation is that the Start or End is set to the Transaction Start Timestamp. So if t2 starts before t1, then if t1 creates a row and t2 deletes it then we will have start=t1 end=t2, but t2<t1 Your tests don't show that because it must happen concurrently. We need to add an isolation test to show this, or to prove it doesn't happen.
Does MVCC allow that? i am not expert on MVCC but i don't
think t2 can see the row create by translation started before