No, according to the guidelines you don't have to supply documentation when logging a challenge.
You might chose to do so any way, it could be of benefit for you if you later lose your qualification (for example if the challenge is related to D/Ts and an important cache changes D/T.), if it's then documented in the log then everybody will understand what happened there.
If the question is really about a owner that deleted a log for you then you should make an appeal to Geocaching HQ. I would expect them to reinstate that log.