SEP 14 and Windows 10 Annoyance

I noticed an extemely annoying symptom with SEP 14.0.1904.0000 on my Windows 10 PC. Every 40 seconds (I've timed it with a stopwatch) the active window on my computer becomes innactive for 5 seconds or so. It's hard to explain, but imagine you're in the middle of typing and somebody walks up and clicks on your desktop with the mouse, interupting your typing. I either have to wait or click back in the window to continue. The active window has a subtle blue outline. Every 40 seconds, the blue fades for 5 seconds and returns.

This only happens when I have SEP installed. I've tried disableing various feature trying to pinpoint exactly what is causing this but so far I haven't had any luck.