tl;dr

A bug with the Preview & Load screen appeared at commit a5ee8af such that a load operation is initiated when the Load button is pressed but the screen does not close until the load completes.

Details

I confirmed via binary search that this bug first appeared at commit a5ee8af (#2955).

As shown in the attached video, when I tee up a large set of files in Preview & Load and press the Load button, the load does begin (you can see the tab appear in the background). But since I'm accustomed to the screen being dismissed and watching the filling load thermometer, I ended up hitting the button again multiple times thinking I maybe mis-clicked and it ends up initiating repeated additional loads of the same data to even more pools.