Miner control the hash right. So if they reduce hashing slightly after difficulty rate adjusted. It will somehow theoretically make the block to be mined more than 10 minutes interval

And then the difficulty rate will go down again, then they will reduce that again.

Last time I check it's 4-19. So miner need to reduce hash after each difficulty adjustment. And vice versa if it's 4-21 or later

CMIIW