I wrote about it before:
According to an article based on research by James H. Kogen in 1978:
"The observation that placing a charged record on a grounded turntable reduces the effect of the charge because the electrostatic field is concentrated between the turntable and the underside of the record, which reduces the original field. When the record is removed from the turn-table, the original voltage reappears."
He mentions that records can be charged up to 30.000 negative volts and it can decrease to 3000 negative volts when placed on a grounded platter.
He also explains that playing a record doesn't cause a significant charge to build up.
"A few minutes of experimentation with such an instrument will show how tenacious and easily produced the charges are. Even wiping the record with damp cloth may produce charges rather than neutralizing them. Incidentally, measurements with these instruments have shown that electrification from the direct friction between the diamond and vinyl is, oddly enough, negligible."
"Any form of friction, motion, or contact is likely to produce charges, and vinyl is one of the most easily charged materials available. Hence, such common actions as removing a record from its jacket or wiping it with a cloth or brush, is certain to produce a charge that will be hard to remove."
That's why brushing should be done before anti-static treatment. The effect of anti-static treatment does not go away even after you play the whole side but can easily be reverted by brushing, rubbing etc.
You can read whole article here:
https://www.worldradiohistory.com/Archive-All-Audio/Archive-Audio/70s/Audio-1978-05.pdf