Multilayer map blending together with different map

Hello

this drawing problem is still happening if I switch from countrywide one level map to regional multilevel map.

Initially the drawing processes correctly but if I'm switched to same level as the countrywide map has and move out of regional map bounds, Locus expectedly uses alternate map of same level (countrywide map in this case), but when I return back to area covered by the regional map (still at same level), the tiles begin exchange randomly between the country and regional map as I roam over regional map area, most often the tile or row of tiles containing map cursor is drawn by country map while surrounding tiles are drawn by regional map. The exchanging tiles are surely covered by regional map. If I zoom in or out to level not covered by country map, the regional map drawing proceeds correctly. After zooming back to same level as country map the problem seems gone, just as when reopening the regional map in maps selector.

I have shot a short capture to show the issue

https://www.dropbox.com/s/846vjmc6i4gb0bb/SCR_20150708_083142.mp4