So just once and then the cannon basically "breaks" and can never fire again.

Now you might be asking "why", so to keep it simple one of my levels that takes a huge inspiration on Minecraft has apparently so many breakable blocks that they stop working altogether and in a level like this where you try to find the stars in diamond blocks, it's not ideal so to speak. I discovered that if I make a cannon deal negative damage on a large radius, it literally fixes those blocks and they can be destroyed once again like normal.

This is the problematic level: https://www.bopimo.com/levels/6986

And I DO need the cannon to "reset" the breakable blocks otherwise they are unbreakable and it's kind of a problem because the whole level hinges on it being fully destructible. Now I guess I know why nobody has done this before it's too much of a headache. I hope Firecat fixes this bug soon, so this workaround is no longer necessary.