Default $orderby _id:1 on where() causing HUGE performance issues

On Mongoid 4 / Moped 2 stable, I am seeing crazy performance issues when $orderby:

is used on a where statement that is doing an $or and looking for a single record. With $orderby its 40 seconds, without it, the same query goes to 1ms.

I checked all of my code and I am not setting a default scope to order by _id anywhere.