Pint is just a generic term, everyone who's been here more than 5 minutes knows that it's only 500 ml.
There is no short measure, no cheating, no shrinkflation, no big deal, no problem.
The Old English do a questionable 500 ml measure including a large head on the Draught Leo, but for 45 baht or 85 a "pint" (depending on the hour of the happy hour) I have not seen anyone send it back.