We just spent ages prioritising our backlog and moving everything to the correct place by Rank, then we moved some tasks into Sprint 3 to check the total estimate counter (we are currently on Sprint 1).
As soon as move around 10+ tasks into that sprint, it reversed the Rank order when they were in that sprint. When we moved it back into the backlog the order stayed reversed.
What's worse, is we thought that perhaps hitting refresh will get them back to the order they were supposed to be originally.
However, this actually caused the order of the ENTIRE backlog to mess up, with different stories jumping to completely random locations, some staying where they were etc.
So obviously all of our work prioritising the backlog was lost, and we really need the solution asap, in order to unblock us to re-order the backlog safely again.