Papa Bear triggers first, giving newly summoned beast in battle +8/+8, but then Thundering Abomination takes over and for some reason undoes the +8/+8, and only then adding +3/+3 to the new minion. The summned minion is now 8/8 lower stats than what it should be.
This happened while I had 2 Abominations and 1 Papa Bear in play