block visualization issue

I have an issue with some files. some parts/lines of the blocks are not visualized but they appears if i zoom in/out.
thes lines appears also if i pass over with the mouse.
do you have a solution for this annoying issue?
below you can see:
- picture 1, file with line not visualized
- picture 2, complete bloch are shown when i pass with the mouse on the block
- picture 3, all the blocks appears completely when i zoom in a bit