All the cables look pristine. While you are correct, simply disconnecting and re-connecting cables can clear up issues, time will tell if that is the root cause this time. I have to admit, I have never seen a loose or defective cable cause an 8-10dB loss in output, but I guess it could happen. In the meantime, I think it would be wise to run with the consumer calibration for several days to see if the problem returns. A Pro calibration takes long enough to complete that I am not anxious to have to discard another one.
Wow...you mantaining a consumer cal and Keith using OmniMic temporarily because a friend borrowed his REW mic--what's the world coming to?
If it's any consolation, I once spent several hours last year trying to ID why a series of mains+sub plots looked so awful post-Audyssey compared to previous runs. Turned out one of our white fluffy dogs stepped on a cable and inadvertedly unplugged a subwoofer.
Fortunately we have a ways to go before our newborn gets that adventurous LOL...