Experiment Manager stucks on "Stopping Trial"

I am sweeping hyper parameters used for training an RL agent. everything is fine until I try to use the "Stop" botton on the top to stop the whole experiment, or when I click on "stop" button of each of the individual trainings. It stucks, and in the background I can see the timer for that training still increasing. Even when I try to close the manager using the X button, it tells me "Experiment is currently running" Stop running the experiment?" what is the problem here. It looks like a bug in the software to me.