HI @a95web!
It looks like this could be happening due to a conflict with your theme or with another plugin.
To be sure, please perform a conflict test by temporarily switching your theme back to Storefront, disabling all plugins except WooCommerce and repeating the action that is causing the problem. If that solves it, then re-enable all plugins one-by-one, until you find the one creating the conflict.
If you can’t perform a conflict test on your live site, we recommend creating a staging site using the WP Staging plugin.
You can find a more detailed explanation on how to do a conflict test here: https://docs.woocommerce.com/document/how-to-test-for-conflicts/.
Let us know how that goes for you!