[Bug] Applying an offset to a geojson layer with PathStyleExtension breaks antialiasing

[colindm]

Description

An example of a geojson layer I created where antialiasing normally works:

new GeoJsonLayer({
id: 'lines',
data: linesDisplayGeojson,
getLineColor: getLineColor,
getLineWidth: SUBWAY_TUNNEL_WIDTH * LINE_WIDTH_MODIFIER,
lineWidthMinPixels: MIN_TRACK_PIXEL_WIDTH * LINE_WIDTH_MODIFIER,
lineCapRounded: true,
beforeId: 'buildings-3d',
updateTriggers: {
getLineColor: [hasActiveJourney]
},
}),

But when I update it to:

new GeoJsonLayer({
id: 'lines',
data: linesDisplayGeojson,
getLineColor: getLineColor,
getLineWidth: SUBWAY_TUNNEL_WIDTH * LINE_WIDTH_MODIFIER,
lineWidthMinPixels: MIN_TRACK_PIXEL_WIDTH * LINE_WIDTH_MODIFIER,
lineCapRounded: true,
beforeId: 'buildings-3d',
updateTriggers: {
getLineColor: [hasActiveJourney]
},
getOffset: (f: any) => f.properties.offset,
extensions: [new PathStyleExtension({ offset: true })],
}),

Antialiasing breaks. If I take the code that works and just add

extensions: [new PathStyleExtension()]

It works fine it's just when I pass in the {offset: true} flag that things break.

An image of a line I drew without the offset flag

VS one with it

Flavors

• Script tag
• React
• Python/Jupyter notebook
• MapboxOverlay
• GoogleMapsOverlay
• CartoLayer
• ArcGIS

Expected Behavior

No response

Steps to Reproduce

Here's an example of a line I generated:

test.json

Environment

• Framework version:
  "@deck.gl/core": "^9.0.38",
  "@deck.gl/geo-layers": "^9.0.38",
  "@deck.gl/layers": "^9.0.38",
  "@deck.gl/mapbox": "^9.0.38",
  "@deck.gl/react": "^9.0.38",
  "maplibre-gl": "^4.7.0",
  "react-map-gl": "^7.1.7"
• Browser: Chrome
• OS: MacOS 15.1.1 (24B91)

Logs

No response