Mortars have regained their effectiveness!

[Rayalot72]

While it's possible that this was John tweaking the game balance, there's also another possible culprit in the patch notes:

Fixed an issue where AOE attacks could be blocked if something obscured vision

Either way, 2.2 should be far easier to complete now, down from being the hardest level in the game to the second easiest.

 

[JohnSlugDisco]

I think you may be right here. It is something I noticed when working on the spider level that if a creature was inside another it was not getting hit. This could also be true of the mortars.