I've noticed it about the hill giant potion in strength dice rolls. It gives you a -1 because of 8 (I assume), then adds +6 to it to make the math work out. This is kind of janky indeed.
By their own janky logic, if my base STR was 12, that should be +1, not -1, and +6 from the potion should give +7!
It's magically knowledgeable chemistry!
