@avishai
First, I would ask, is there anything you have recently changed? Installed? Updated? Code added?
Work backwards…
Any new plugins?
And plugin updates?
If you do the standard debugging (deactivate all plugins except WooCommerce, WC Vendors and WC Vendors Pro)- does it work properly?
If not, then if you temporarily switch from your theme to the Storefront Theme– does it work properly? https://wordpress.org/themes/storefront/
Also, check that you have all dashboard pages omitted from the caching from your cache plugin.
Please try these steps and let me know the results.