Qt Assistant: when called with -enableRemoteControl option, gets stuck for significant time

If Qt Assistant is called without arguments, it runs immediately, and everything seems working fine. But if I run it with -enableRemoteControl option, it gets stuck for significant time (about 10-30 seconds), after this timeout, it can accept commands and perform actions. But not always: sometimes, my MATE environment is completely frozen, so I had to switch to the console Ctrl+Alt+F1, and kill assistant.