I also thought you were referring to a TPS. I have occasionally noticed the same thing on my non-TPS TT2 on the rare days when it’s quiet enough to hear it in this house! The non-TPS turntables have their motors connected directly across the mains and are therefore fed with whatever waveform is coming out of the wall socket. If the mains is particularly distorted or noisy that can sometimes cause a slight vibration in the motor which is probably what you’re hearing. This is the main reason why dedicated clean power supplies such as the TPS which feed a pure sine wave to the motor can produce an improvement in the sound. It’s almost certainly nothing to worry about.
Time flies like an arrow.
Fruit flies like a banana.