Road disappears in my 3790T

[shinjizh]

My 3790T is TW modeol and I save Europe map in my SD card.
I disable TW map and move original TW map file in other folder.
After power up, 3790T will only load Europe map, Europe 3D file and Europe DEM file.
However, some roads will not show on my screen.
If I do power-on again, lost road that on previous power-on will show, but another road will disapper.
I don't know how I could correct this situaion.
Please refer to below picture.
In the rectangle, roads disapper.
Bus statoin and store show the road is there, but not show in the map.