I guess it's easier to recount the trail of events:
Swirling/Static in left channel, left channel goes out mid-use (happened before in a channel years ago, ended up having to replace a k216 somewhere after checking some of the behavior near the power rails). At this point I was able to power up both channels and only the left one wasn't functioning properly.
Right channel was fine throughout this time - rails weren't acting up etc.
While powering on (only) the faulty left channel afterward I saw something spark near the output CCS and take out the stacked LED's
Left it alone for a few days, tried out the right channel just to verify that it was still working so I could compare voltages etc. Problem as stated in the previous post - rails all measured like the limiting kicked in
I do think I've messed with the current limiting at one point, but my recollection is kind of fuzzy - I was actually going to search through this thread because I feel like I've encountered it before