Some of the most noticeable examples:

Btw ants have 20hp while rest of the bugs have 4

The health and hitbox issues of the ants have been fixed, as well as the rest of the ambient mobs. All other hitbox problems will be fixed over time.

The majority of hitboxes have been taken care of now including all the worst ones shown above. They currently do not adjust with growth but that is a separate issue that will be looked into in the future.