I was going to make a new topic about this, but I searched the forums and found this.
Burrowing -- when an Elite Shierker has momentum cast upon by a level 6 opponent, making it 11/5, the AI often burrows it. This reduces the power down to 5. If the AI unburrows it, the power returns to 10, not 11, basically negating the +1 power from momentum. Bug -- burrowing rounds down, and then 'forgets' to round back up when unburrowed.
Burrowing -- when a Pest becomes 2/5 from Eclipse and is then burrowed, the power remains at 2. I believe this isn't a bug due to Eclipse always assiging +2/+1, but I've thought this interaction strange and I'm not sure if it's intended.