Im thinking on this one.. its not very typical and when I was in the business I did over 2000 turntable setups. So lets start with what its not
1) stylus problems exhibit throughout the record
2) alignment problems don't manifest this way
3) General arm problems are agnostic to position on the LP
The times I have seen issues with groove position have all been mechanical issues
platter
noise at the juncture between inner and outer platter assemblies. mat design or aging issues where the mat isn't making good contact with the inner grooves
tone arm
binding in the bearings because the platter is tilted relative to the arm. Issues with the antiskating mechanism binding or increasing drag during travel due to corrosion or dust. Counterweight mods touching the gimble at the end of play
1) stylus problems exhibit throughout the record
2) alignment problems don't manifest this way
3) General arm problems are agnostic to position on the LP
The times I have seen issues with groove position have all been mechanical issues
platter
noise at the juncture between inner and outer platter assemblies. mat design or aging issues where the mat isn't making good contact with the inner grooves
tone arm
binding in the bearings because the platter is tilted relative to the arm. Issues with the antiskating mechanism binding or increasing drag during travel due to corrosion or dust. Counterweight mods touching the gimble at the end of play