Unable to resolve Jira issues from pull requests: Sprint field is empty

Issue Summary

Unable to Resolve Jira issues within Bitbucket PRs because of the Sprint field being empty (although previously filled out) during resolution.

This is reproducible on Data Center: Yes

Steps to Reproduce

1. Launch Bitbucket Server 7.17.4
2. Launch Jira Software 8.13.11
3. Create an application link between Bitbucket and Jira
4. Create Project and Repository in Bitbucket and push a couple of commits
5. Create a Scrum project in Jira
   1. Assign the Jira Workflow (jira) to the Story issue type and publish the changes
   2. Associate the Done status to the Resolved status
6. Under Administration > Issues > Screens, configure the Resolve Issue Screen
   1. Add the Sprint field
7. Create a Project link between the Bitbucket Project and the Scrum Project
8. Create a Pull Request and review the Diff
9. Create a task on one of the diffs and Create a Jira issue out of it.
   1. Select Story as Issue Type and ensure a Sprint is selected before creating the Issue
10. Open the new issue within the PR and click on Resolve Issue
    1. Notice that the Sprint field is empty and when resolving the issue, it throws an error "Number value expected as the Sprint id."

Expected Results

When resolving the issue from the PR, the Sprint field should be populated with its actual value from Jira

Actual Results

When resolving the issue from the PR, the Sprint field is empty and thus the issue cannot be resolved.

Workaround

Resolve the issue in Jira or remove the Sprint field from the Resolve Issue Screen