I'm not quite sure what your motivation for doing this was, but:
In Server_Support.cs from line 1715 you are doing something to rewrite the entire brick destruction code, presumably for floating bricks, but not only is it unnecessary to do in such a fashion, it breaks stuff. Whatever brick I try to break, floating, not floating, default, not default, doing the addvelocity and fakekillbrick method not only breaks mods that rely on instant feedback, it feels unrealistic. In addition something, possibly from that section, breaks undoing the bricks, consequently breaking mods that rely on the undo stack. I'm sure this was just a hitch since you're an experienced coder, but just in case I suggest you always use default methods and not try to replicate default visual effects.