Edit outlines + vertices drawn incorrectly

There is somthing very weird going on with the yellow selected lines and the vertices in editing mode - and it is not restricted to the hole cutting mode, obviously, but maybe it shows up there for me in the most prominent fashion.
I opened bc_2m_lakes.shp and selected the geometry edit tool, as you see from the screenshot. Then I panned a lake to be in the center, selected it and zoomed in to the feature. After zooming in the yellow line and the vertices seem to be oddly displaced in a chaotic fashion. (See attachment) When I deselected the featue and selected it again, without zooming, the vertices were located at the right locations.

When does this happen? Here are my best hypotheses:

• If you select a feature that you did not select before for editing.
• If you then pan and zoom to the feature
• If you do several pan/zoom in actions quickly one after the other, while the drawing is not yet updated to the previous one.

Sorry but even I cannot reproduce this EVERY time.