The case

We use to have a Moodle 3.0 enviroment with LDAP synch. When migrating to a different hosting party we changed from LDAP to SAML2. Sofar I know their where no issues during this process. 

 Last summer we have upgraded the same enviroment from 3.0 to 3.3.1 And since that upgrade - when I click at Siteadministration > Notifications I get a warning for new settings - LDAP server. 

It shows the mapping of 2 custom profile fields. 

When I try to save the changes, the notification will not go through. It stays. 

On a test server we have tried to delete the custom profile fields. 
Which helped, but when we set new custom fields the notification returns. 

Strange thing is that we are still using SAML2, and there are no users that still have LDAP as a authentication. As well that LDAP is disabled. 

see also discussion: https://moodle.org/mod/forum/discuss.php?d=360310#p1453965