If the teleportation, caused by eating a chorus fruit, fails, it seems like you start losing saturation faster. If there isn't any valid spot to teleport nearby, after eating about 5 chorus fruit you will lose all the saturation and 2 points of hunger: then eating another chorus fruit will not fill your hunger points back.

Steps to reproduce:

• go above the middle of an ocean, at an height of about y=100, so that there are no valid spots around you to teleport while eating a chorus fruit
  -make sure your hunger bar and saturation are full
  -stand still on a block and start eating chorus fruits: after about 5 chorus fruits your saturation will be depleted and you will lose 2 points of hunger
  -keeping eating chorus fruits will fill visually your hunger bar, but you will instantly lose 2 points of hunger again (your hunger bar will keep staying at 18 points)