Honestly.. just keep asking "why?". Most engineers ask "why" to the surface level questions. E.g. "Why is the bug doing this instead of that?" A: "Oh, because

Honestly.. just keep asking "why?". Most engineers ask "why" to the surface level questions. E.g. "Why is the bug doing this instead of that?" A: "Oh, because this conditional does thing..simple, just fix this conditional. Solved!" Then the issue pops up again... The engineer probably didn't ask why enough. The should have investigated more... "Why did the original author choose this logic instead of the alternative? Was it purposeful, or was it a truly logical mistake?". If it was purposeful, why was this alternative not considered? What was Product's intentions here?" etc. etc.