Here's the console output from the attempted tag editing:
Properties dialog refresh: 0:00.000071
Properties dialog display refresh: 0:00.001172
AFCFileRefOpen called. Handle: 1, Path: /iTunes_Control/Music/F45/Beat.mp3, Mode: 2, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 0, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 10, Read: 10, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefTell called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 16384, Read: 16384, Ret: 0
AFCFileRefTell called. Handle: 1, Position: 496853, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 481513, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 4, Read: 4, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 4, Read: 4, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 1040, Read: 1040, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefTell called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 0, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 10, Read: 10, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 0, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 480469, Read: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666424, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666392, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 32, Read: 32, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666296, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 128, Read: 128, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666264, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 32, Read: 32, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 0, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 10, Read: 10, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 0, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 480469, Read: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666424, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666392, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 32, Read: 32, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666296, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 128, Read: 128, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666264, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 32, Read: 32, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666424, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666392, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 32, Read: 32, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666296, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 128, Read: 128, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666264, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 32, Read: 32, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666168, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 128, Read: 128, Ret: 0
AFCFileRefSetFileSize called. Handle: 1, Position: 5666296, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666296, Ret: 0
AFCFileRefWrite called. Handle: 1, Requested bytes: 128, Ret: 0
AFCFileRefTell called. Handle: 1, Position: 5666424, Ret: 0
AFCFileRefSetFileSize called. Handle: 1, Position: 5666424, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 0, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 10, Read: 10, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 0, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 480469, Read: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 0, Ret: 0
AFCFileRefWrite called. Handle: 1, Requested bytes: 480469, Ret: 0
AFCFileRefTell called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 0, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 10, Read: 10, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 0, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 480469, Read: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666424, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666392, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 32, Read: 32, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666296, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 128, Read: 128, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 5666264, Ret: 0
AFCFileRefRead called. Handle: 1, Requested bytes: 32, Read: 32, Ret: 0
AFCFileRefSeek called. Handle: 1, Position: 480469, Ret: 0
AFCFileRefClose called. Handle: 1, Ret: 0
Properties dialog refresh: 0:00.000269
Properties dialog display refresh: 0:00.002132
And here's the I/O test:
Starting read tests...
AFCFileRefOpen: Ret: 0
AFCFileRefOpen Mode: 4, Ret: 0
AFCFileRefRead Read: 0, Ret: 0