`symbol` layers using `symbol-placement: line` render above `line` layers at zoom < 13.7 in Mapbox Standard

[MobileD2]

mapbox-gl-js version

3.28.0

Browser and version

Chrome 151.0.7922.75

Expected behavior

A line layer added after a symbol layer (intended to render on top) should remain visually above the symbols at all zoom levels.

Actual behavior

When zooming out past ~13.7 in Mapbox Standard, symbol layers placed along lines are hoisted into a top-level overlay pass, rendering directly on top of line layers regardless of beforeId, slot, or execution order.

Link to the demonstration

No response

Steps to trigger the unexpected behavior

1. Load Mapbox GL JS (latest v3 release) with mapbox://styles/mapbox/standard.
2. Add a symbol layer (planned-dots) with symbol-placement: "line" along a LineString.
3. Add a line layer (route-line) on top of planned-dots (e.g. map.addLayer(routeLine) called after planned-dots).
4. Observe correct z-ordering at zoom > 14 (route-line covers planned-dots).
5. Zoom out past 13.7 and observe planned-dots hopping on top of route-line.

// 1. Add Planned Dots (Symbol Layer - rendered first/below)
map.addLayer({
    id: 'planned-dots',
    type: 'symbol',
    source: 'route-source',
    layout: {
        'symbol-placement': 'line',
        'symbol-spacing': 20,
        'icon-image': 'dot-icon',
        'icon-allow-overlap': true,
        'icon-ignore-placement': true
    }
});

// 2. Add Route Line (Line Layer - added second to render ON TOP of dots)
map.addLayer({
    id: 'route-line',
    type: 'line',
    source: 'route-source',
    paint: {
        'line-color': '#2a82e4',
        'line-width': 8
    }
}); // Drawn after planned-dots to sit on top

### Relevant log output

```shell