Ahh yes of course.
Except I made no changes to that hook between v1.5.7 and v1.5.6. Also other plugins that handle the hook before my plugin receives it can directly affect hook calls on my plugins if things that aren't meant to be null when this hook fires off, are null. Or FP logic can change between updates causing the same problem.
So like I said, I need insight as to what is happening on the server when these errors are thrown. Alternatively I can throw you a copy if you register on my discord to test that has debug.