Your subject says "not working as expected" and you refer to the RHV DR guides.

My comment is that in my opinion HCI architecture is not expected to work / be supported for active active DR scenarios as described there.

But you can follow general GlusterFS indications for solving split brain scenarios, like this one:

and / or submit your question also to GlusterFS mailing lists

or see if here you find useful information for supported configurations, quorum setup to prevent split brain conditions, ecc:

HIH,

Gianluca