I downloaded your package and activated Theme Twenty Seventeen, disabled all non Toolset Plugins, and then I saved the post you mention.
It said:
Field "E-Mail-Address" not updated: Please enter a valid email address.
I checked the value there, it's a valid email address.
Anyway that error seems the issue why it's not saving (since it fails, with an error message)
But, even if I leave that field empty, the WYSIWYG still doesn't save it's values.
I started picking apart the site (deleting plugins, theme's, unused files which are not part of a WordPress vanilla install).
I discovered a JS error in your install:
TypeError: Cannot read property 'getNotificationManagerImpl' of undefined
This is from the TinyMCE instance of WordPress.
Hence I thought eventually the install is corrupt, and replaced all WordPress files as well.
It did not help.
So I proceeded stripping the site, deleting Custom Field Groups, recreating new ones, etc. At no avail.
Only deleting all fields post types and then recreating new ones solved the issue.
The database showed a lot of corrupted data before I did this.
As example, post field groups where saved with a value of ,,,,
This seems to have been provoked by hidden errors, related to:
RevSliderBaseAdmin->onAddMetaBoxContent() and, Toolset_Theme_Integration_Settings_Front_End_Controller_avada->get_keys_from_filter(). Both functions seem to produce a PHP Notice, which is not replicable locally.
One function is from Revolution slider, and the last in the call stack.
The Toolset_Theme_Integration_Settings_Front_End_Controller_avada method is ours, it's used when you have AVADA and Toolset Installed, but this function came earlier in the call stack.
I am not able to replicate that error, but that might be due to some settings I miss.
Now, the problem is of course that I cannot ask you to recreate 300 Custom Fields.
But I do not know where the error sources from, and this will require time to fix on your specific site - I will need to send this package to a Developer for further investigation
What can help me a lot is:
- if you recall after what step this stopped working
- if you saved ANY form of HTML, JS, CSS or whatnot, that is not a simple string, in any of the fields.
==> If so, this might have caused a database corruption that is irreparable if the code somehow managed to manipulate other data.
This sounds impossible, but is not.
I have seen JS added within script tags in a Visual Editor that disabled the entire Toolset Layouts List.
I also saw that you use 3rd Party ShortCodes within our Fields, which seem to use a custom syntax and return complex data.
Such data can also corrupt the database
Of course all this is very unlikely but we see that there is a form of corruption ion how things are stored in the database.
Hence, at some point some thing must have sneaked in.
Starting with the JS error you should see on your live site as well, I guess there is as well a plugin who registers some JS code that conflicts with the native WordPress TinyMCE JS.
A quick test can be to disable all WYSIWYG Fields on that post type and re-try, but I suspect that won't help, since the data already is corrupted.
I will ask a developer to help us on this.