2 millimeters is quite small and gives (gave) the crew lots of time to isolate and fix the problem. If it were real sabotage, they would have drilled something quite a bit bigger.
Bigger would be noticed right away, lots of little ones can add up to a sudden major catastrophic failure in that environment.
Just some worker from the old Soviet Union pretending to work because the company is pretending to pay him. Russian high tech stuff is known to be on the shoddy side, but works and is easy to repair; extra holes are a plus because the product is lighter and therefore less expensive to produce ... Russian thinking.