[Update]
The issue was finally solved by increasing socket timeouts:
- in the agent by using the option _socket_timeout_ms=<milliseconds> (default is 30000 ms);
and
- in the profiler UI by specifying -Dyk.controller.connect.timeout.ms=<millis> (default is 5000 ms = 5 s) and -Dyk.controller.read.timeout.ms=<millis> (default is 30000 ms = 30 s) in <user home>/.yjp/ui.ini