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I've cleaned the disc. There appears to be some very minor abrasions. Could that be causing it?

Error 'Posix error - Input/output error' occurred while reading '/dev/rdisk2' at offset '8121612288'
Error 'Scsi error - HARDWARE ERROR:TRACK FOLLOWING ERROR' occurred while reading '/BDMV/STREAM/00000.m2ts' at offset '8121612288'

Anything that makes parts of the disk unreadable will cause read errors. If the scratches are minor, sometimes waxing the disk will "fix" it long enough to read; otherwise, you may have to have it resurfaced.