Disclaimer - affects all versions from 19w07a and above not 19w08b , I wasn't able to find snapshot versions below 19w08b.
There are still more updates to come up, so why did Minecraft say, "Finally Complete!" in the image given?! Is this an Easter egg, or a bug, or the truth?! Pls be an easter egg.
This is NO bug as all appearing splash texts are saved in one file (version.jar\assets\minecraft\texts\splashes.txt, can just be oppened trough a zip program like 7Zip), the "Finally complete!" splash text is in the file, too. So this Works As Intended.