Every game I get up to 25-75% "down" ping can hits huge numbers. Doesnt happen on any other game. No adjustment to home network. started maybe 2 patches ago.
Looks like client side message as changed while going to spectate, so more then likely the issue has been looked at. Will update ticket if new issues arise.
With my testing it seems to be on the person being spectated client, not with the users client.
When I reproduce, I noticed a few things
1. That the match timer remains unchanged in my friends list as well as the overlay.
2. If this issue effects one player it effects all of them.
example...