yes , on my RX580 and monitor AOC 24G2U i have the same problem , on 144Hz memory clock never drop . If i change to 120Hz work fine and drop to 300Mhz . If i create custom 143Mhz refresh on CRU software also work fine and drop to 300Mhz .
ASRock RX7900GRE Steel Legend, i5 13600K, Asrock Z690 PG Riptide, 32gb ddr4 4000mhz.