LDAP Cache never end when the wiki is active; New LDAP not in the right groups

My XWiki is connected to an LDAP. The wiki is very active (1.5k connection a day) and uses an LDAP cache.

Issue : When there is a new user added to the LDAP, he can connect to XWiki but not with the correct rights until the activity is fully stop for a long period (which never happen).
Temporary used workaround : We clear the cache manually. We're about to create a scheduler job but we don't consider this as a good solution but only a temporary one

It looks like, since users constantly come in, that the cache do not update and the timer reset after each connection and so the cache live forever.