Why did this break Adobe Camera RAW?

Camera 50sii. Lens Helios 44 58/2 80 serial. Opening the files off the memory card.

Loaded up the files in Bridge, and opened the image in ACR. Did what I do, and then I remembered, oh yeah, manual lens profile needed. Set it to the Helios and then dinked around because why not. Started playing with distortion in optics, and when I push it 200, this split happens. Any idea what's going here? Trying to understand it so I can use it. It goes away when I turn it back under 200, so it's not causing a crashing.

It's possibly just a bug in the arithmetic.

You could report it to Adobe, but I wouldn't worry about it otherwise, just make sure you keep below 200.

Not worried about it, just trying to understand what's going on, so I can do it with intent. I would love to get the whole image looking that blueish color that isn't supposed to be there.

EDIT: Ok, I have figured out what's probably going on. The distortion and the masking in ACR aren't playing quite right here it seems.

If you resize the image and then do whatever you've done do you still get the split when you push it past 200?