You will almost always run into "undocumented" items during engineering work.
That is why I always used a notebook for everything, design notes, debugging notes and especially meeting notes. Nothing beats a written comment when everyone else is running off faulty memories. I have won a large number of arguments by pulling out my meeting notes and showing them what I documented during the meeting. Beats a bad memory every time!
When you come across something missing or wrong in documentation about a device or component, don't keep it to yourself. Make sure all of you co-works know about it and in todays world, send a note to the manufacturer. Everyone wins. Communication is the key to successful engineering.
Just my opinion.
DAB
