colocated proxy regions issue

Hello All,

    We have 2 groups of cache servers and 2 proxy regions of group2 on group1 which should be colocated. Below is the configuration from group1 cache.xml

<region name="regionA">
        <region-attributes refid="PARTITION_PROXY" statistics-enabled="true">
                <partition-attributes redundant-copies="1" recovery-delay="5000" startup-recovery-delay="30000"/>
        </region-attributes>
</region>

<region name="regionB" >
        <region-attributes refid="PARTITION_PROXY" statistics-enabled="true">
                <partition-attributes redundant-copies="1" recovery-delay="5000" startup-recovery-delay="30000" colocated-with="regionA"/>
        </region-attributes>
</region>

But whe we are trying to start the servers it's failing with illegalstateexception as below if group1 starts first.

Assign buckets command issued for /regionA

Exception in thread "main" java.lang.IllegalStateException: Cannot create buckets, as colocated regions are not configured to be at the same nodes.

Does anyone have any thoughts on this?