This happens on 1.2.40 but has been the bane of my existence for many, many versions. If I am trying to select an area and the area exits the window due to zoom level, when I reach the edge the mouse cursor gets teleported down on the Y axis to below the active canvas and becomes impossible to reposition on that axis. The X axis continues to move normally.
I also encountered this situation when using version 1.2.32, and the 1.3 version I am using now does not seem to appear… Well, maybe Windows is a little more compatible? 