Hey,
I was having exactly the same problem with one of my sites.
After troubleshooting I located the problem to the IThemes security plugin – https://www.ads-software.com/plugins/better-wp-security/ which seems to now be conflicting following the WooCommerce update.
Once you disable the plugin the error disappears.
Hoping for a quick update to the problem since it’s my preferred security plugin.
Hope this helps.
John
