Several Materialized Views become Invalid everyday on a Fresh 12.1.3 instance - Must Use ADADMIN

My customer has recently completed the implementation of a new E-Business suite 12.1.3 instance. Database is release 11.1.0.7.

Every day, he notices that several Materialized Views (MV) have become invalid. He has to launch adadmin and recompile invalid objects. This validates the MVs but only until the next day.

Materialized Views of concern are:

OWNER        OBJECT_NAME                              OBJECT_TYPE          STATUS
------------ ---------------------------------------- -------------------- -------
APPS         OZF_EARNING_SUMMARY_MV                   MATERIALIZED VIEW    INVALID
APPS         MSC_PHUB_CATEGORIES_MV                   MATERIALIZED VIEW    INVALID
APPS         MSD_DEM_SCN_ENTRIES_MV                   MATERIALIZED VIEW    INVALID
APPS         OE_ITEMS_MV                              MATERIALIZED VIEW    INVALID
MSC          MSC_ITEM_HIERARCHY_MV                    MATERIALIZED VIEW    INVALID