Unable to run a Memory Calibration, or turn on Revision Control.

Hey, can i ask you one more question? There is a massive bug in my map where creature zombies are invisible for some people, not not for others. I have tried everything and cant find a fix.
Do you have any suggestions on what i can do to get this issue seen? Ive reported many times in the past weeks and it has got no recognition. If you dont know, no worries and i appreciate it.