I've got the same "problem". Defender doesn't seem to have an issue with the exe (scan) and after a check with Run->cmd sfc/scannow there wasn't any malfunction either. So it looks like Ccleaner has some unjust dislike of the exe file. However, maybe i am mistaken . The pc does funtion normally though. Considering you have had the issue as recently as i have, i would feel like a Ccleaner-thing...
Regards, Nico