Hmm, I see a pattern in where the error comes up. This is a V-Max 2 formatted disk, so it uses sector headers that follow the pattern
64 XX YY XX YY .... 46
Where XX and YY are EOR'd together to determine the sector number. In every case where I see a bad bit, it's in the $46 end-of-sector marker byte, which contains the illegal GCR combination of three consecutive 0 bits. And in every case where it was bad, it read in as a $5B instead.
Gauntlet Deeper Dungeons (another one I'm having trouble with getting a decent image from) also uses this $46 byte. Bad Street Brawler uses it too. Most of the other games with this format use $4E as the end marker, likely due to issues with the $46 byte.
64 XX YY XX YY .... 46
Where XX and YY are EOR'd together to determine the sector number. In every case where I see a bad bit, it's in the $46 end-of-sector marker byte, which contains the illegal GCR combination of three consecutive 0 bits. And in every case where it was bad, it read in as a $5B instead.
Gauntlet Deeper Dungeons (another one I'm having trouble with getting a decent image from) also uses this $46 byte. Bad Street Brawler uses it too. Most of the other games with this format use $4E as the end marker, likely due to issues with the $46 byte.