Some indexed Jira issue keys are not returned in REST response

Issue Summary

In Bitbucket /rest/jira-dev/latest/updated-issues, end-point is used to return list of Jira issues that were updated since given "sequenceNo". This end-point accepts a parameter called "maxResults" which helps in paginating through the results. But while paginating some results are not returned on pages > 1st page.

Steps to Reproduce

1. Create a repository.
2. Push some commits in this repository which involves 5 different Jira issue keys.
3. Note down the current time in milliseconds.
4. Perform re-indexing of this repository using following curl command

   curl -v -u <ADMIN_USER> -p -H "Accept: application/json" -H "Content-Type: application/json" -d "{}" <BITBUCKET_URL>/rest/jira-dev/1.0/projects/<PROJECT_KEY>/repos/<REPO_SLUG>/reindex?withCommits=true
    

5. Hit following URL in browser with authenticated user session - <BITBUCKET_URL>/rest/jira-dev/latest/updated-issues?sequenceNo=<<SEQUENCE_NO>>&maxResults=5 and note the results.
6. Hit same URL with maxResults=2
7. Hit same URL again with sequenceNo equal to "newSequenceNo" received from last response and maxResults=2

Expected Results

2 Jira issue keys are returned in the result which are equal to 3rd and 4th received in step 5

Actual Results

No issue keys are returned

Workaround

Currently there is no known workaround for this behaviour. A workaround will be added here when available.

Impact

This impacts Jira integration where missed Jira issue keys won't show latest branch/PR/commits information in dev panel if more than 50 issues are updated at same timestamp OR re-indexing updates more than 50 Jira issues. End-to-end issue will not be observed until JSWSERVER-20190 and JSWSERVER-20612 are fixed, because different error will happen before this issue is observed.