Also occurs on: 19w44a, 19w42a, 19w41a, 19w40a, 19w39a, 19w38b, 19w38a, 19w37a, 19w36a, 19w35a, 19w34a.
Couldn't add to versions that it occurs on top of the page, sorry.
Respect for staff,
Far
I can still reproduce it without Optifine, (Vanilla Minecraft).
The same reproduce method.
Full respect,
Far
/:/ Edit: New images added, without Optifine.
I can see this has been taken over by Avoma, which is probably a good thing.