It teleports you and your catch to the top of the middle tower.
I've also seen this happen to Deathy on stream, today it happened to me and I think it happens pretty consistently if you lash ult there.
Note that all these instances occurred in the same match, so the problem is fairly severe and easy to unintentionally replicate.
Match ID (all clips): 33355436
I've had this occur in at least 5 different matches with varying distance from the middle pillar that it teleports you on top of, sometimes in excess of 20m.