runtime datasource TEST/FLUSH unavailble alternately on members of Server Group

Customer can see a specific DS dropdown under runtime instance #1 but when they go to instance #2 its unavailable. If they shift-f5 and reload it appears. When they navigate back to instance #1 its no longer available, until they also shift-f5 refresh... and so on.  See attached screenshot.

Customer running in domain mode, one domain node and two host nodes.
Behavior is the same in Chrome 84.x and IE 11.959.x

Issue occurs on EAP 7.2.8, hal-console-3.0.21.Final-redhat-00001-resources.jar, didn't see that version 3.0.21 on dropdown .