syl.center doesn't contain the right value

OS: Windows Pyonfx version: 0.9.13 This file contain the font, the input ass file, the output ass file and the script used to generate the screenshot: [test.zip](https://github.com/user-attachments/files/20274453/test.zip) Here is the result of Output.ass  If I uncomment the first line (a.k.a the ktime), I get this:  As you can see, the initial line and the produced line are clearly not correctly aligned. If I correct the x of the \pos tag, I can get the result I expect: