Refer to the exhibit.

An administrator implements the MultiZone feature. The administrator sets up five zones as shown in the exhibit in this configuration:
-Zone A has six controllers that form a cluster.
-Zone B has three controllers that from a cluster.
-Zones C, D, and E have a single standalone controller each.
A total of 13 VAPs are created across the five zones, Aruba Mobility Controllers (MCs) in Zones A, B and C run ArubaOS 8.1.0.1 MCs in zones D and E run ArubaOS 8.1.0.2. Some APs do not join their respective data zones.
What could cause this problem?