As reported by @marco-c in matrix:

https://firefox-ci-tc.services.mozilla.com/tasks/FzWJ02RQRSC0dXB3-SN5jQ is part of https://firefox-ci-tc.services.mozilla.com/tasks/groups/F61bIEKnQqWTvbJYX3aKXg, but if I search for its name in the search box, it isn't found

Also @Eijebong noticed:

It's also not scheduled and the task group reports 0 unscheduled tasks