My iMac has been in sleep mode and will randomly turn on with a bright purple glitchy looking screen. When you move the mouse to wake it up it clears the screen. Seems weird and has been happening for at least a week now, with nothing new installed on the computer since purchase. iMac is less than 6 months old and want to make sure this gets resolved ASAP. Thanks.
iMac 27" 5K, macOS 10.14
Try an NVRAM reset:
Reset NVRAM or PRAM on your Mac - Apple Support
FWIW, I gave up on the Sleep function years ago. Ever since the inception of OS X there have been Sleep related issues. And even more lately. I just use Display Sleep and keep it set for 15 minutes so I'm not burning the screen. That way your Mac uses very little power over Sleep and is ready to use at the touch of a key without any grogginess. UNIX based systems were made to be always on and they’ve been running busy servers 24/7 for decades.
iMac wakes itself up from sleep with purple screen
