Different individual SmartThings hubs are using different zigbee channels.
For the V1 hub, it was fixed at the time of manufacture and you couldn’t change it at all.
For the V2 hub, every time you do a full factory reset the zigbee channel gets reassigned randomly, but it might even reassign the one you just had, and you don’t get to specify what it should change to.
So if you’re willing to do a complete reset, you can just keep doing it until you get the zigbee channel where you want it to be. Good to know if you’re doing a complete rebuild, but otherwise probably not too useful.
But the main point is that where your ST zigbee transmission is might be very different from where another SmartThings hub is.