When the code is out there, is it possible that a third-party will modify the existing exFAT projects based on this "leak", and get them to work properly and out of userspace?
Anyone who has read the Samsung code is "tainted" with the knowledge of Samsung's proprietary techniques which may be copyrighted, so those people may well introduce copyright violations into the code.
In clean-room reverse engineering projects, the people who are examining the system to be reverse engineered are never the same people that actually write the new clean code, thus avoiding the taint of proprietary knowledge.
If this is someones paid project (who's paying?) to disrupt exFAT work, its doing pretty well, only took about a month to possibly destroy the whole area of operation. Effective. Probably pretty cheap.
So, follow the money. Who benefits? Could they (or a subcontractor of a subcontractor, etc) be hiring someone to sabotage a project?
There's a critical matter of identity here. We're discussing this as if its a J random hacker individual scenario. It might not be, and there's no reason to suggest it goes either way. Also looking at the github record this individual has apparently never done anything else, and didn't "exist" until recently, which is ... odd.
This situation needs to be looked into. I would give it maybe 75% chance of pure cluelessness and flaming, and maybe 25% chance of being something... more complicated; or worse.