On access scanner exception not stored for external media

when I configure on access scanner exceptions for an external usb storage device, the exception is only remembered while the device is plugged in. If I unplug it and plug it back in, I still get alerted to the signatures on the drive. I do security research and am not worried about the signatures, but cant find a way to permanently exclude them.

for now I have completely disabled the on access scanner.

Thanks!