RSS feed dependent on user's latest activity view, which is confusing, unexpected, indeterministic

This issue is related to https://gitlab.com/gitlab-org/gitlab-ee/issues/29990 but is fundamentally wider in scope.

Summary

The RSS feed generated link/token produces different output, depending on which Activity report the user last selected.

Steps to reproduce

Log in. Click on Activity in the menu bar. Open the Feed/Subscribe button on the right in a separate window. Note the URL and output. Go back to Git/Activity and click on a different report, ie

• Push events
• Merge events
• Issue events
• Comments
• Team

Refresh the Feed URL. The output will change. (It loosely corresponds to selected feed, but because of the existing bug, I cannot verify this correspondence is 100%)

What is the expected correct behavior?

The feed view should either be comprehensive and contain ALL events, or there should be a separate feed token for each report. It makes NO sense to make the feed dependent on what the user last selected on any given browser.

Results of GitLab environment info

Gitlab CE 12.1.4