I agree that is the weakest element. Applicability largely hinges on what qualifies as a “police investigation” or “legal proceeding” which I have been unable to get a clear answer on. But, from a layman’s perspective, it seems like a police interaction which may lead to a use of police powers either should count or our legislative bodies should change the law to make it count as that appears to be in line with the spirit law to guarantee that all pertinent evidence to a crime be discoverable.

It's simpler than that. Even intent to get youtube to censor/not publish it is not concealing it from anyone, and especially not concealing it from an investigation/ the justice system, which is the clear intent of the law.

If not being published on YouTube were the criteria for concealment, then wouldn't the person making the recording also be guilty if they simply decided not to post/share it?

Preventing publishing or distribution isn't concealment.