Stretched / distorted map display

In some zoom levels maps are displayed stretched along the north-south direction. When the zoom level is 200m or larger is looks fine. When I zoom in the map is distorded by some amount specific to each zoom level. 5m and 12m are by far the worst of the set.

My Montana 700i came with software version 8.20 installed. I upgraded to the latest version and is did not make it better... perhaps it made it worse but I'm not sure of that.

Is it normal? How to fix?

- Screen orientation (portrait / landscape) does not mattter.

- Auto zoom does not mattter.

- Map type does not matter.

- The map is not distorted along the x or y axis of the screen.

- Intermediate zoom levels that can be selected with pinch-zoom are distorted too by varied amounts.

I attached a set of screenshots with zoom levels from 300m to 5m. The map is centered on a structure that has an almost perfect 90 degrees angle and I rotated the map to align it to the screen. The map is distorted at all zoom levels up to 120m, but some of them are pretty bad. 200m and above IMO are fine.