Text Based World Seeds Broken

I generated a new world from a seed I use often for build planning and discovered that when using a text-based string, it does not properly (or at least consistently) convert to a numerical seed.

From my testing, this bug was NOT present prior to 20w20a.

I've attached screenshots of worlds generated from seed WLLBYUG (-2143500864), which does not match the seed as shown by the /seed command in those worlds. However, when directly inputting the numerical seed, world generation proceeds as expected.