Not snapping to grid properly and other weird issues

I haven’t been working with aseprite for a while now and opened it for the first time today.

I noticed some weird things while playing around:

-it snaps to every single pixel not to the 16x16 grid I set

-eraser is kinda weird

-when I draw there are some pixels that are left out

-it sometimes makes those weird diagonal lines

screencap I made

this is really frustrating, any help is appreciated

thanks a lot!!