DPI Software Limitation?

I am experimenting to find the best DPI for my laser for photos, I am using a basic gradient jpeg image. I have noticed that I cannot go above 498 DPI when using the Jarvis image mode. I have tried 508, but the output is not correct.

I have manually tested a 508 DPI BMP version of the gradient with passthrough selected and it works as expected. Is this is software limitation or bug?

My maximum DPI seems to be frustratingly between 498 and 508 available.

Please see my images attached.

As you can see below 508 using lightburn mode causes a weird loss in the gradient that isnt present at 500 (498 in software)

You can see the results below 500 are a lot better.