Black bar on worlds preview image

Basically, when i close the world, it saves an image to set as the cover. It worked until yesterday. Today (5 April) it doesn't work anymore. It shows this black bar and a little triangle on the bottom (as shown in the image).

THIS HAPPENS ALSO IN THE LATEST PREVIEW 26.20.23/24!

Steps to reproduce the issue:

1. Create or open an existing world.

2. Close the world

Expected result: Perfectly fine preview image

Actual result: Really bugged image