I've never seen it be buggy, but it will often remove unnecessary parens. For example: (a * b) + (x * y) becomes a * b + x * y.

This the same code, but I often use parens for semantic grouping or to be 110% sure the operator precedence is correct for a particular formula. It's not a dealbreaker, but it does remove some of the meaning I was trying to imbue on the code.