iThemes security file change detection

Hi,

For the last week I have been receiving this message:

iThemes Security has noticed a change to some files in your WordPress site. Please review the logs to make sure your system has not been compromised.

My log changes are of this sort: wp-content/cache/supercache/www.my site, and they occur at the same time each day. However,if it the changes were as a result of cacheing, why are the alerts showing?

I contacted my hosting company who told me that there is no malicious content on my site, meaning that it is not a hacker. Does anyone know why this alert would be showing?

Thanks