I have an etx 125 and don't get any slewing on start up. The handset just beeps after a couple of seconds and then goes into alignment mode. If Michaels suggestions don't work, Are you going to SGL star party? If so you can try my handset and see if it works with your scope? Alternatively you could try and update the handset software here https://www.meade.com/support/auto.html you will need a serial connector to connect the handset to a pc, you might have one already with the scope, if not, I can send you a picture of one and you can buy it. Hope that helps.
Steve