I have been cycling through all dates before publishing a watch face but if you use fixed width even though it shows correctly and fits fine in Creator the date can show up blank on the actual watch.
I had to quickly fix these two since the date didn’t work:
It’s the total width of the date element. You always have to allow extra room because WearOS is finicky for some reason. If you look at the width box, you can fix it in one of two ways. Unclick the fixed width checkbox or just set the width to 360 which is off screen on both sides. Either one will work.