CAS and LDAP backend not working together anymore

[cyworks]

Hi,
Since the beginning of the year the CAS and LDAP backend not working together anymore.
In the database when OCA\UserCAS\User\Backend is set for a user only CAS working not the client or Owncloud form. When OCA\User_LDAP\User_Proxy is set only client or Owncloud form working.
We don't know where is the problem, we have this error on the log :
User already provided by another backend(OCA\User_LDAP\User_Proxy !== OCA\UserCAS\User\Backend), skipping."}
Returned account has different backend to the requested backend for sync

Thank you for your help

[ownclouders]

GitMate.io thinks possibly related issues are #287 (User from backend LDAP disabled), #60 (LDAP Cache), #55 (How Quota Default field of LDAP wizard works?), #26 (LDAP Plugin stops after Importing first user), and #317 (Can't delete LDAP users).

[cyworks]

We already check all this issues, we don't think it's any of this problem because when we set OCA\User_LDAP\User_Proxy for a user backend in oc_account table it works.
The problem is that we cannot use two backend for one user (LDAP and CAS backend).