Error while saving.

As we know, Enfold Theme handles the new vs. old editor using its own setting. WIth the latest Enfold update, suddenly when using the classic editor the custom fields in The Events Calendar posts wouldn’t save. (This did not seem to be an issue when using the new block editor). Saving the post reset the custom fields, and an error message occurred in the message line under the post text input box: “Error while saving.” As I used the process of elimination, here is what I found:
– The issue was not actually confined to the events posts – the same issue existed with all posts, except that most posts don’t have custom fields so it went unnoticed at first. The issue may have gone undetected for several weeks.
– I consulted with SiteGround on the problem and they assigned a senior technician, who was unable to resolve the issue within the scope of the support they provide. They eliminated server/hosting configurations as a cause.
– I created a staging site to test the issue further by deactivating ALL plugins on the site. The issue continued with ALL plugins deactivated, so I concluded that the issue isn’t related to The Events Calendar, LearnDash, WooCommerce etc.
– Next I tested the Child Theme (child of the Enfold Theme) to see if the customization of the Child Theme might be the cause. However, the same issue existed when the bare Theme was used – so the customizations are not the issue.
– Next I changed the Theme to a standard WP Theme (2020 Theme) and found that the issue does NOT occur when the Enfold Theme is replaced by a different Theme.
– My conclusion is that the problem is the Enfold Theme, maybe connected to its own “classic editor” option built in.
– Finally – I have found a work around for the time being. Installing and activating the “Classic Editor” plugin (from WordPress) seems to override the themes version of the classic editor and allows saving posts. However, the error message still appears under the post content box, even though the posts seems to save OK.

Is this a known problem the the latest release when using the classic editor with posts with customs fields (like Events Calendar)?