Only 3 indexes are moving to Schedule state irrespective of no. of parallel index creation request

Only 3 indexes are moving to Schedule state irrespective of no. of parallel index creation request. I tried with 10, 20 and 30 indexes in parallel and each time after 3 indexes move to schedule state, all indexes created in sequential manner.

Steps to reproduce: - 

1. Create a cluster in 2 index nodes.
2. Add a bucket, scope and collection
3. Run -

   curl -u Administrator:password -X POST  http://10.112.190.101:9102/settings -d '{"queryport.client.waitForScheduledIndex": true, "indexer.debug.enableBackgroundIndexCreation": false}'

1. Create few indexes (say 30) in parallel so that few indexes are in "scheduled for creation" state.
2. Monitor index creation in Index workbench

Logs:

 
https://uploads.couchbase.com/MB-46380/46380/collectinfo-2021-05-19T094320-ns_1%4010.112.190.101.zip
https://uploads.couchbase.com/MB-46380/46380/collectinfo-2021-05-19T094320-ns_1%4010.112.190.102.zip