Do you know what PBCN stands for? "Powered BREAKABLE Clone". But considering that it doesn't break normal BCLN, it's probably just an oversight that it breaks PBCN
I think the breakable elements should be broken by dest, and sing. I also think clne and pcln should both be completely indestructible like diamond. I have it this way in my mod. It works fine this way, see my reusable bombs