Gradients with negative phases acting weird

[Rebble3000]

I've recently noticed that gradients with more than 2 colors appear incorrectly when their phase is below 0.
I don't think this is an intended feature, since the gradients do appear correctly when their phase is -0.0, but don't when their phase is -0.1.

How to reproduce

Compare the deserialization results of these inputs:
<gradient:#FF0000:#00FF00:#4444FF:-0.0>Hello, World! Lorem Ipsum</gradient> and
<gradient:#FF0000:#00FF00:#4444FF:-0.1>Hello, World! Lorem Ipsum</gradient>

My results both on paper-1.21.4-232 and on webui.advntr.dev:

[SoraHjort]

Yeah, it appears to be reversing the gradient's color order. as well as introducing a strange offset.

The offset also becomes more obvious if the second line has the colors reverse order.

<gradient:#000000:#00ff00:#0000ff:#ff0000:0>╒═════════════╕</gradient> Phase: 0<newline><gradient:#ff0000:#0000ff:#00ff00:#000000:0>╘═════════════╛</gradient> Phase: 0

<gradient:#000000:#00ff00:#0000ff:#ff0000:0.1>╒═════════════╕</gradient> Phase: 0.1<newline><gradient:#ff0000:#0000ff:#00ff00:#000000:-0.1>╘═════════════╛</gradient> Phase: -0.1

note on the first line how the blue shifted slightly to the left in the second image compared to the first, where as the second line just jumps all the way to the right.

[SoraHjort]

After searching through issues and pulls to see if anyone has mentioned anything similar, I saw a closed issue and a merged pull from several years ago that might indicate that there was a regression at some point.

Issue-889
Pull-896

In them they mention that gradients with more than two colors bugs out the phase offsets.

After checking it, two color gradients work perfectly fine with negative numbers.

gradients used: #000000:#ff0000 and #ff0000:#000000

As you can see in the image, they're working as expected. No flip, no sudden offset.