Bitbucket unable to handle "large" PRs through the UI

[p]

We have been fielding issues approximately weekly for the past few months with "large" pull requests that Bitbucket cannot merge through the UI.  Occasionally the Diff tab cannot even be viewed.  Bitbucket has been observed to consistently time out during one or more of these activities for "large" PRs:

• Displaying the Diff tab of a PR
• Evaluating whether or not the PR is eligible to be merged (I assume during merge conflict detection)
• Merge action

When this happens, retrying seldom "fixes" it.  Waiting for a period of time, like overnight, and trying again seldom "fixes" it also.  This issue seems to affect some PRs consistently, and not others, consistently.  It is not random.  Some PRs just can't be merged, and others can.

Because this has happened many times, I have tried to figure out what is different about the PRs that cannot be merged.  In all cases, there are either many files changed, OR there are many commits.  I speculate from this that it is the total "size" (ie the difference in repository clone download size with vs without the commits included) of the merge that causes this, once the size passes a certain threshold.

We are able to work around this issue by performing the merges locally on our workstation.  But this is a time suck for us, and we believe that especially because this is not a one-off issue, we have a legitimate expectation that Bitbucket must be made capable of doing this without manual intervention.

The particular example at this moment is here, with only a few commits, but I cannot yet see the number of files changed: http://sdlcscm.hiw.com/projects/BCWEB/repos/spa-stay-mgmt-test/pull-requests/34/overview

We do not have the luxury of waiting on this PR, so I am about to merge it now using my workstation, but first I made copies of the source and target branches and a duplicate pull request that you can use to troubleshoot the issue.  I added everyone on the team as reviewers.  The duplicate pull request is here: http://sdlcscm.hiw.com/projects/BCWEB/repos/spa-stay-mgmt-test/pull-requests/36/overview