excessive Ram use in single player

After the 1.20.80 update i notice my RAM surging to 95% of 31.7GB, in single player only. I don't know exactly what all that means but the game becomes jittery and laggy after 5 minutes of playing, and does not drop back down until i close the game entirely, minimizing it drops it too but hen surges right back up (see screen shot) render distance at 50 (recommended and used to be fine). realms seem to only take up 50%