Carburetor Spring

[Fazerider]

I’m just guessing that the TPS was bolted down such that it was applying sideways pressure on the shaft, i.e that its axis was slightly off to one side rather than concentric with the shaft. There should be enough free play available between the screws and the slots in the TPS (when they’re loose) to be able to get the TPS centred.
Another cause for the problem might be that the TPS is pressing on the end of the shaft, but it’s hard to see how that could happen unless there’s a lot of dirt in there or the TPS is non-standard.