Mystery!

Some weeks ago my Cyrus CD t transport stopped reading my discs, so I brought in for repair. The technician said it played perfectly for him and  he couldn’t find anything wrong with it. So, I brought it home, and sure enough, no matter what I tried the discs would not load. Brought it back to the store and he said he still couldn’t find a problem. Loaded perfectly for him. Went back to the store today with my own discs and they loaded without a problem.
Brought it home, and now it works!

What’s going on????