[Improvement] Possible thread issue in `LockManager.java`

### What would you like to be improved?

Synchronizing on a parameter synchronizes not on the parameter itself, but on the object assigned to it. Two different threads running the method in parallel could pass two different object instances into the method as parameters, completely undermining the synchronization.

### How should we improve?

Investigate and improve

Start by reading LockManager.java and identify the method that synchronizes on a parameter. Trace how that method is called and inspect any existing concurrency tests or test entry points. Done means the synchronization concern is resolved and concurrent behavior is covered by a regression test.

Written by the indexing model from the issue text.