Steps to reproduce:

Open the attached "Repro-PB5-ResolvedStyleGap" project
Select "PB-5 > 1. Open repro window (Editor panel)" from the menu bar
In the "PB-5 resolvedStyle vs rendered" window, compare the "resolvedStyle" and "rendered" values under rows 2–5
Compare them with the control rows 6–7 ("padding-left" with the same values)

Actual results: "resolvedStyle.columnGap" and "resolvedStyle.rowGap" return the value as authored, not the gap that is rendered:

"column-gap: 10%" on a 400px row: the boxes are 40px apart, "resolvedStyle.columnGap" is 10
"style.columnGap = Length.Percent(10)" set from C#: 40px apart, "resolvedStyle.columnGap" is 10
"column-gap: -10px": 0px apart (the layout clamps it), "resolvedStyle.columnGap" is -10
"row-gap: 10%" on a 200px column: 20px apart, "resolvedStyle.rowGap" is 10

Expected results: "resolvedStyle.columnGap" and "resolvedStyle.rowGap" return the rendered gap (40, 40, 0 and 20), the same way "resolvedStyle.paddingLeft" returns the rendered padding for "padding-left: 10%" (40) and "padding-left: -10px" (0)

Reproducible with versions: 6000.7.0a3, 6000.7.0b3, 7000.0.0a1

Can't test with versions: 6000.0.79f1, 6000.6.3f1, 6000.7.0a2 (the row-gap and column-gap properties are not available)

Tested on (OS): macOS 26.6.2 (Apple Silicon)

Notes: It also reproduces in Play Mode with a runtime UIDocument. Px values are reported correctly, and the layout itself is correct in every case.