FYI, The Missing Guardian quest in lower Craglorn is broken.

I've submitted a ticket a couple days back and they returned to me saying they are aware of the issue and some day they will fix. So don't get your hope to high.

https://help.elderscrollsonline.com/app/answers/detail/a_id/21005/track/AvOdDwrtDv8S~Q6CGrYe~yIL2UEqmS75Mv_V~zj~PP9c