How can they not know? If you see unexpected behavior in some subsystem, it should be easy to pinpoint. e.g. in a UI context, timeline shows wrong data. Start

How can they not know? If you see unexpected behavior in some subsystem, it should be easy to pinpoint. e.g. in a UI context, timeline shows wrong data. Start there and work backwards. I can only imagine it's hard to pinpoint if the code is not factored well.