Why daily uploads in wp-content/uploads/uag-plugin/assets

Hi,

we use of astra + spectra (uag) on our non-profit association site.
I notice that uag loads daily or nearly daily a lot css files in wp-content/uploads/uag-plugin/assets/xxxxx (x in [0-9]), even if no article is modified (for example on weekends).
my monitoring script detects this behavior.

why that ?