System Analyzer doesn't display task activity

I'm trying to use the System Analyzer window to verify that all my threads are executed in the right time. My program has four threads, one of which has to executes every 10ms and has a priority osPriorityHigh. When I take this one out of my program, I'm able to see the other three threads on the System Analyzer Window, but when I put it back and run the program with the four threads, the System Analyzer Window only displays the thread actions but not the threads themselves (see image below). How could I solve this problem? It is a problem of the EventRecorder configuration (I left it by default)? I'm using CMSIS::RTOS2 (RTX5), the target is a nRF52840.

Any help would be appreciated.