I recently updated my iMac to High Sierra and IMMEDIATELY started having problems with my keyboard lagging and then typing random letters. I’ve made three calls to Apple and they say they haven’t heard of this problem, yet I’ve seen many others are having the same problem. I’ve reset the SMC and zapped the PRAM, debugged the Bluetooth, ran ONYX and rebooted many times with no luck. This only happens with the wireless keyboard. I never had a problem until the update. Any others have this problem or have a solution??