Thunderbolt 3 and a dock

[jpfeif]

A little bit of background: I am a part of a club that has are meetings at a school, we are allowed to access the laptops in the school that are all equiped with Thunderbolt 3, the laptops we use dont have the drivers installed for Thunderbolt 3, but displays work and thats all that matters to us. We extend the monitors accross the two monitors, they are having a problem where the Thunderbolt 3 docks they use decide not to extend accross the two monitors when the teacher plugs in the next morning, and instead decide to mirror, are we doing anything wrong or are they attributing a problem to us when its just Windows being Windows.  They use HP laptops with HP docks this is the dock: https://store.hp.com/us/en/pdp/hp-thunderbolt-dock-g2-with-combo-cable.