Could not edit README from overview when "Require issue keys in commit messages" enabled

Refer to https://confluence.atlassian.com/bitbucket/link-to-a-web-service-283641959.html

If you've enabled "Require issue keys in commit messages" option, editing README.md on the Overviews page results in error 500.

Workaround:
Either disable the option, or access README.md from the source and save with issue link