GitLab Activity Feed - Link takes you to GitHub when clicking ID
This screenshot shows a webhook event that was fired as a result of an issue being submitted on GitLab. If you click the
#30 in that link (it all seems to be one link as a result of no formatting - this is true for all GitLab webhook events, unlike GitHub webhook events where you have styled them) you are taken to GitHub, not GitLab.
Clicking anywhere else in that link, will take you to GitLab as expected.