Cannot create primary index when N2N Encryption is enabled.

Reproducible on Neo build 7.1.0-1361

https://s3.amazonaws.com/bugdb/jira/qe/collectinfo-2021-12-08T150123-ns_1%40ec2-3-222-192-34.compute-1.amazonaws.com.zip
https://s3.amazonaws.com/bugdb/jira/qe/collectinfo-2021-12-08T150123-ns_1%40ec2-34-239-233-168.compute-1.amazonaws.com.zip
https://s3.amazonaws.com/bugdb/jira/qe/collectinfo-2021-12-08T150123-ns_1%40ec2-44-193-18-182.compute-1.amazonaws.com.zip
https://s3.amazonaws.com/bugdb/jira/qe/collectinfo-2021-12-08T150123-ns_1%40ec2-44-201-45-76.compute-1.amazonaws.com.zip
https://s3.amazonaws.com/bugdb/jira/qe/collectinfo-2021-12-08T150123-ns_1%40ec2-54-236-31-169.compute-1.amazonaws.com.zip

When running AWS performance testing for N1QL, creation of primary index via:
CREATE PRIMARY INDEX primary_idx ON `bucket-1`
Fails with output when node to node encryption is enabled on the cluster. :
"errors": [\{"code":5000,"msg":"GSI CreatePrimaryIndex() - cause: Index creation for index primary_idx, bucket bucket-1, scope _default, collection _default cannot start. Reason: Fails to create index. There is no available index service that can process this request at this time. Index Service can be in bootstrap, recovery, or non-reachable. Please retry the operation at a later time.."}],
An example of the unsuccessful  job can be found here:
http://perf.jenkins.couchbase.com/job/Cloud-Tester-Dev/62/console

Here is the same test, but without n2n enabled - it successfully creates the primary index (at 15:47:19 in the log output):
http://perf.jenkins.couchbase.com/job/Cloud-Tester-Dev/61/console

The N1QL query is done via a rest call, it has been altered to use https and port 18091 when n2n is enabled, all other rest calls work fine via this method. The REST call also failed when attempted manually.

Finally, when trying to execute the query via Couchbase UI, the same error message appears, but the UI does successfully recognise the index node in the server tab.