Images disappear from the server

Hello!
I have installed wordpress multisite with a main domain and a subdomain. For more than a month I am having a recurring problem with images from the main domain. Every Tuesday or Wednesday the images in the wp-content / uploads folder on the server disappear. My hosting provider says that you do not see any server-level anomalies. This issue only affects the primary domain, the subdomain is working properly. Has anyone ever had this happen? Can it be multisite configuration failure?

Thanks!