This.
Yes, D2 is only connected at one end.
This seems to be a KiCAD bug. I deleted D2 from the schematic, loaded a new netlist, but didn’t delete it from the board layout. it should have remained on the board, but unconnected. Somehow, though, it was in the rat’s nest, connected at one end, so autorouting connected it to a trace. Passed DRC without errors, both before and after autorouting.
See Strange behavior with unused component
I sent this to fab at Seeed in Shentzen. The board works; it just has an unused footprint.