I'm using v5.44.6575 and randomly two ccleaner64.exe will start up, I don't see any scheduled tasks starting them or anything, they just start up on their own, I also use Avast ( 19.1.2360) if that means anything.
I found something in the task scheduler called CCleaner Update, I wonder if that was causing it.
I just ran the scheduled task again and the two ccleaner64.exe reappeared, so it seems that was the cause of it.