So I went back and tested the last five versions, and it shows up in all the 2020. As soon as I click somewhere in the network grid, the cursor returns to normal.

It still always shows the cursor outside of TD, or even in the Palette, but not the network editor or parameter panel.

I have found that the ONLY time the cursor disappears when I release MMB is when I release while the cursor is over the border of the parameter pane (when the cursor switches to double-headed sideways arrows) I MMB Click and start dragging, but certain elements start highlighting or changing the cursor when I pass over them.