I deselected the “Snap to pixel grid” option, and still frames snap to the pixel grid. All the other types of layer don’t, only frames. Essentially, both coordinates and dimensions of frames are not allowed to be decimal (sub-pixel), except if you change the value manually in the sidebar, but as soon as you “touch” the dimensions on the canvas, it will pop back to the nearest pixel. I’m wondering if this is a bug or not.
To me this is a problem because it generate weird behaviors, for example here in the picture, I’m trying to anchor the “Frame 2” vertex to the rectangle’s vertex, you can see the red “snap indicator” is there but the frame is not allowed to stay in between the pixels, so I cannot place it where I need it. In this specific case I could move the rectangles over the frame, but in complex design that could be not feasible. That’s why it seems weird.
By the way, does this happen to you also?
I tried different browsers and the behavior is the same for me.