Scrollable area bug?

I have a scrollable area which scrolls only vertically because I set the width of the canvas in the related container to then width of the scrollable area.

Everything works fine, but I want to drag horizontally in the canvas. This works until I move vertically in the same drag. Then the pointerUp event is fired. This causes a problem for me and I wonder if this is an error. PointerUp event without lifting your finger?