Update on the bug: I could not reproduce it on the web version, but in the process I have found something else.
(I already emailed the videos to Renan, I'm posting this here to the benefit of all future lurkers).
1. The ball goes through Sturdy bricks sometimes, but it does not break nor bounce back after hitting them (and indeed this does not cause a miss). I guess this is somehow related to Color Piercing or Piercing (or both).
2. Easy Cleanup activates twice if the latest Respawn happens before all the coins have been caught or fallen off screen (I had Lv 1 on both perks). Here's what happened: the ball hit the second to last brick, the last one is automatically destroyed, but then another one gets respawned and quickly destroyed again.
The first one is a bit jarring, the second one is so marginal that I doubt it even warrants the time investment (but I thought you better knew about it).
Also, two more non-bug related updates:
3. Boring cheat – I found out a way to farm points: if you have Respawn Lv 3 or 4 you can endlessly hit the same cluster of bricks, and if you manage to put the pluck in a comfortable position (i.e. straight line) it's very easy to farm plenty of coins with the aid of appropriate combo perks. No video though, this happened on the app while I was playing casually (it's quite easy to reproduce, though). I wouldn't do that because it's mind-numbingly dull, but still I'm not sure this kind of play is intended or if it should even be allowed.
4. Combo balancing – one thing that makes the best strategy overly dominant is the way combo resets abruptly with everything other than Compound Interest, which pairs exceptionally well to Coin Magnet (which is in itself instrumental to scoring high). If the other combos would scale down accordingly (i.e. 1 coin less when you hit the walls/ceiling/puck – or at least drop some percentage, but not all of the combo at once). This would instantly make many more strategies and combinations viable, because right now it doesn't make much sense to pair Compound Interest to any other combo perks (except in very specific circumstances).