Failed to decrypt volume after ReadyNASOS service or process was restarted

I have 2 RN628X in use as well as one RN526X and now all of my NAS devices occasionally have the issue that something triggers tge ReadyNASOS service to be restarted. This is quite annoying, but more so because I have encrypted the volume and have to put in the USB key to have the volume decrypted again. This is quite annoying as one of the RN628X's that hold my back-up is located a couple of hours drive from where I normally am. Is it possible that the encryption key is stored in memory untill the machine is powered off and that it only needs to be inserted when a fresh restart is initiated. And of course a solution for these ReadyNASOS service restarts would be appreciated as well.