Round Corners vs CP Filter Round Corners accuracy

In order to get a 100px corner, I need to enter a radius of 98 into the Round Corners. Likewise a 200px corner requires I enter a radius 196.

However if I copy the setting using the cog menu and add the Round Corners as a Custom Parameter Filter I get a different result. If I export an OTF the values are different. A CP value of 98 creates a 98px corner. Is this a bug?

It might have to do with the visual correction setting. It might not work in the CP.

It isn’t disabled when I apply it as a filter. With visual correction deselected, shouldn’t the result be the same as the radius entered? I’d expect some change in value if it was selected.

I’ve been using both the normal filter and the CP recently and I’m having to adjust the values to get what I want. For example applying a radius of 40 results in a corner of 41u. There’s something iffy going on with the accuracy of Glyphs, it isn’t as accurate as it should be. See my other post here Rounding errors when scaling when none should occur