Did you get refund? I will need the piece of information before starting my review
OP hasn't responded yet. For the record: I don't need the refund, but if it's a bug, it should be fixed. And if this should work the way it did, it should be clearer in the Rules.
It was added to the winner's amount? (I don't know for sure).
It has increased the "ending time" with 140+ blocks? (I am 99% sure it did).
This means that it was seen as a smaller (non-winning) separate bid, no matter the originating address.
So it can be "the expected behavior", just it
must be documented.