I ran out of ability to reproduce this but I believe this is critical
I logged into my account on Steam, on Windows, and went and bought a new warband to get a new team /slot set up.
When I went to Guild Wars to set my Defense teams and all of them were set to my PVP Defense team. Which is not how I left Guild Wars Defense last round.
I saw this on my other account early this morning and didn’t think much of it but now the only thing I did on both of these accounts was get a new warband team slot.
SO Make sure to double check your Defense teams before the clock switches over to start GW.