Screen keeps waking 3 to 5x per minute

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Astronaut

Screen keeps waking 3 to 5x per minute

Does anyone else experience this? My phone is suddenly waking while the screen is blacked out and locked. I initially thought it was notifications, so I cleared notifications. Then, it kept happening. It happens when on WiFi and on 4GLTE. I uninstalled the latest new app I put on (A1 SD Bench), and it's happening still. I then booted in safe mode, and the screen kept waking up every 5 to 13 seconds over a period of about 5 minutes. I am lost as to what it could be. I thought that safe mode would isolate it to an app if it didn't happen in safe mode, but that didn't help.