This tweet seems to me that there's a suggestion that Mason quit because of Postecoglou.
View: https://x.com/RobDorsettSky/status/1929596006020071842?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1929596006020071842%7Ctwgr%5Ef518c1c8d3b5f5ba6c0085f9662badf3ff35fec0%7Ctwcon%5Es1_c10&ref_url=https%3A%2F%2Fwww.tottenhamhotspurnews.com%2Fnews%2Ftottenham-coach-quits-says-he-wouldnt-sign-contract-under-postecoglou%2F
Not necessarily, the wording is a bit weird.