MIcrostation Line styles disappear, with only custom line text showing

Good day all, 

I have a peculiar problem with my custom line styles. 

I do reticulation work, on 2D MicroStation using custom line styles denoting types of conductors use, for example, Fox: F, 035 AAAC : 35.

I have noticed that when i leave my laptop on, and it goes to sleep mode, and when i activate it, the lines in my already open MicroStation file dissappear.

I am currently using MS V8i, SS4, 08.11.829, i7 6500U, 8GB RAM computer. 

I have attached the screen grabs of a sample area, so you can see what i mean. 

 Figure showing section without lines. 

After restarting the application, (MicroStation), here is a screen grab of what it actually should look like.:

I am not sure why this is, has anyone ever come across this before?

Thanks in advance. 

Greg,