I have been using a company computer running Ubuntu 22.04. There are frequent and unexplained problems, like segmentation faults, stack errors, files disappearing, computer freezing or not booting, or turning off immediately after I turn it on. I don't know what to do. The IT staff came to my office to check the computer and said "it was all good." I am not allowed to boot from a USB stick or enter BIOS or open the case. I ran a command line memory check several times with no errors. There is an NVIDIA card, but it's running X.org and usually headless. I mostly set up tasks via SSH.
Idk about RAM but cables can cause that. Still randomly disappearing files sounds more like an issue of the drive itself. Though it should cause the system to randomly freeze afaik. Or it can just be malicious remote control but that's highly unlikely.