Man, allow me to add my, "I'm glad it's not just me" to the discussion.
For me, this same thing started happening to me with the update to version 5.45.6611 x64.
Just simply starting CCleaner puts the Active Monitoring icon down near the clock, and then it stays there even after closing CCleaner.
Active Monitoring is UNchecked in the program.
I notice also that, every time I start CCleaner, the Active Monitoring keeps getting reinstalled back into MSCONFIG Startup.
And as someone else stated, I too have to kill the process using Microsoft's "procexp64" just to get it to close.
Well, just knowing this is a legitimate issue experienced by others puts me at ease.