As luck would have it, SkoolKit 1.0 shipped with bugs in the disassembler,
sna2skool.py. The bugs don’t affect the building of the Skool Disassemblies themselves, but will produce an incorrect disassembly from snapshots containing one of the following instructions: ‘XOR IYh’, ‘XOR IYl’, ‘XOR (IY+d)’, ‘SBC HL,SP’, ‘ADC HL,SP’, and the ED-prefix versions of ‘LD (nn),HL’ and ‘LD HL,(nn)’.
Here at pyskool.ca I don’t tolerate bugs, so in response I’ve pushed out a bugfix release of SkoolKit. You can get it from the SkoolKit page.
Of course, if you spot any other bugs, don’t be afraid to report them with appropriate amounts of indignation and bitterness.