Here is one I did recently…
These mwbc’s are all on the same legs. (plenty of tandems)
But isn’t previously about 15 years ago?
More recent editions added a requirement for a common means of disconnect for MWBC even if both hots are not on the same yoke. They want to eliminate neutral current if only one hot was turned off and work was done on the neutral
Since the vintage of the panel was not stated, i added a comment that may have applied. I don’t remember which edition added the requirement.
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Right, so it is a defect that should be noted every time we see mwbc’s not tied together regardless?
I understand the implications between the two, (same leg and not same leg)
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added in 2008.
(B) Disconnecting Means. Each multiwire branch circuit
shall be provided with a means that will simultaneously
disconnect all ungrounded conductors at the point where
the branch circuit originates.
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Is it a defect if not up to current standards? It could have been compliant when installed.
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True. It is obviously more of a danger when on the same legs
Correct, there is the potential of 2x the neutral current if both hot are on the same leg.
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The picture quality is poor, so I really hate to even mention anything about it. I see two different breakers installed in the panel. The bottom double pole 20-amp breaker also appears to have 14-gauge connectors, one is colored black. The wires attached to the 30-amp breakers may also be undersized. The wire on the 15-amp breaker also appears to have some discoloration on the sheathing.
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Just curious how can you tell from that mess? Were you able to trace the black and red conductors back that are on the same tandem to see that they both were in the same cable?
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No, I didn’t… I tried (briefly) 
But there were other issues. (Several oversized breakers), so I just called for further eval.
I also couldn’t determine if that many tandems were allowed, but I believe the newer sq d panels allow it on almost every slot
The label needs to be checked to see if tandems are allowed. There are still many, of all brands, that do not accept any tandems.
Also, with the removal of the 42 circuit limit, the panel still needs to be follow the listing. The removal is not retroactive.
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That would not be a MWBC. I would think that someone who claims to be an electrician would know that; especially one who says his answers are based on the NEC.
Since you don’t know what a Multiwire Branch Circuit is, I’ve included an excerpt from the 2020 NEC with the definition.
I am quite aware of what a MWBC is. I am also aware that it is possible that a miswired one would not have a voltage potential between the 2 hots and still be sharing the neutral. This would have the potential to overload the neutral exactly as i stated.
Now i see why people have you on ignore.
If there is no potential between the ungrounded conductors, then there is NO MWBC.
The concept really isn’t that difficult. I thought perhaps you’d be able to grasp it if you saw the NEC definition. Apparently, I gave you more credit than you deserve.
By the way, “Potential” means Voltage. Maybe that’s what is confusing you. In other words, there has to be a Voltage between the ungrounded (aka Hot) conductors. Is it starting to sink in a little?
Are you saying it is safe for two ungrounded conductors on one leg sharing a neutral is safe simply because it does not meet a definition? Did you never teach your apprentices about this occurrence or the dangers?
You must have a serious reading comprehension problem. I’ve never said anything remotely like that. Any apprentices I taught would have known what a Multiwire Branch Circuit is close to the beginning of their apprenticeship. They were also taught not to misapply terminology merely because they don’t understand something.
Using your convoluted logic, you can call anything that you don’t understand a mis-wired Multiwire Branch Circuit.
There is an industry standard definition of Multiwire Branch Circuit. I tried to help you by providing the NEC’s definition. The fact that you don’t like, or can’t understand, the definition is your problem. The industry isn’t going to change a definition just because you can’t understand it.
And still no answer to the question.
Tell us what you think is wrong.