[Gameplay] Tahm Kench Ult Bug

I was playing Tahm Kench in Hide and Seek dominion in a custom, when I ulted and tried to teleport somewhere by myself it wouldnt work and would just go to the shortened 10 second cd. A team mate tested trying to enter my ult and ended up getting eaten as if I had used my W. My ult then went on max CD but only had the W effect.

Not entirely sure how to recreate the bug, but I think it happened because my ult was interrupted by Gragas body Slam.