Inconsistent numbers of Pull Requests popping up from Development Panel

Summary

When the Dev Panel is updated (automatic pull from JIRA to Bitbucket Server or push from Bitbucket Server to JIRA), clicking Pull Request (PR) link will display all the linked PRs with the right total number of them (in a pop-up window). However, if the page is refreshed afterwards, the pop-up window still displays all the linked PRs, but the total number is incorrect (until the next update of the Dev Panel).

Steps to reproduce

1. Link JIRA (7.2.4) with Bitbucket Server (4.10.0)
2. Create 4 Open PRs in Bitbucket linked with 1 JIRA issue
3. Decline 1 PR and Merge another 2 PRs (so the Dev Panel is updated)
   The Dev Panel of the JIRA issue says there's 1 Open PR (refer to the note below):
   
4. Click the PR link to open the pop-up window
   Expected behavior: The window displays 4 PRs and the total number is 4 correctly:
   
5. Refresh the page and open the pop-up window again
   Unexpected behavior: The window displays 4 PRs but the total number is 1 incorrectly:
   
   Looks like it's following the number of the 1 Open PR in the Dev Panel

Notes

1. The expected behavior is the pop-up window always shows the right total number of PRs displayed there (4 in this example).
2. The Dev Panel doesn't display all PRs in all statuses. If there're multiple statuses as in the above example, the priority order will be Open -> Merged -> Declined. So in the above example it displays 1 Open PR.
3. At step 5 above, if we wait until the Dev Panel is updated, the pop-up window will display the total number of PRs as 4 correctly again.