I have an approximately one month old Windows 10 computer. For the last few days, I've been having odd activity: the system seems to switch context to another application briefly, then switches back. I typically see the title bar or the text box I'm typing in flash on and off twice, indicating loss of focus, then its restoration. If I'm in the middle of typing, several letters will be lost (they never appear on the screen; I don't see them in another application that I have open). It usually happens once a minute, though some minutes I don't see anything; I'm not sure if that means the behavior isn't happening, or I'm just not doing something that would make it obvious. Yesterday it seemed to start at the same second each time; today it seems to be taking a full minute from the end of the last event to the start of the first event, so each event starts a few seconds later in the minute. It is not connected to when the system clock changes the minute.
I wondered about malware, but Avast hasn't found anything, even when I did a boot-time scan; Malwarebytes found only a PUP which is actually legitimate. Task Manager doesn't show anything running that seems particularly odd, though I won't claim to know every single task running. I've rebooted multiple times since this started with no apparent impact on the situation. I'm stumped for how to resolve this.