Whenever I toggle a modifier, the attack rolls are set to automatically roll the damage twice for crits.

I created the following weapon:


And this is its attack roll:


But once I set up the following modifier, which adds +1 to weapon attack and damage rolls:



This is how the attack roll became:



So I was wondering if this is a bug or something that's intended, and if there is a way to toggle it off.

I'd also like to know if there is a way to automatically roll damage twice on crits (and only on crits). Thanks in advance!