Note that if you aren't logged in, things do appear to be visible, so the only failure case I have seen is logged in but without any treeherder scopes.
Bug 1595942 Comment 15 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
Note that if you aren't logged in, things do appear to be visible, so the only failure case I have seen is logged in but without any treestatus scopes.