Full System Scans running at 8pm every couple of days and I can't turn them off

I have Norton Internet Security version 18.6.0.29.  I have turned off the Idle Time Scans and have no Full System Scans scheduled.  I'm still getting a Full System Scan automatically running at 8pm every day or so.  At first I tried turning the Idle Time Scan to Weekly and then Monthly but it didn't seem to change the frequency of the scans.  I have now turned them off and they still run.  They also run when I'm actively using my computer as well and not when I'm idle.  What can I do to stop these automatic scans from running?  It's driving me crazy since I'm always using my computer at 8pm.  I always stop the scans when they start but I want it set so they don't even start.  Please help.