Subject: Symbol labels on vector-tile polygons — collision hiding and cross-tile duplicates

mapbox-gl-js version

v3.1.0

Browser and version

Chrome / Edge (recent). Not browser-specific in our testing.

Expected behavior

Each visible polygon should show one readable label. A polygon clipped across tiles should not produce multiple labels for the same feature.

Actual behavior

We consistently see two problems:

Collision hiding — With default placement (text-allow-overlap: false), many labels disappear in dense areas even when the polygon is visible and zoom constraints are met. Labels flicker in/out while panning.

Cross-tile duplicates — When one polygon spans multiple tiles, the same name often appears 2–4 times near tile boundaries, because placement runs on each tile-clipped geometry fragment.

We also tried text-allow-overlap: true with text-ignore-placement: true and symbol-avoid-edges: false. That shows more labels, but duplicates and overlap get worse. We have not found a satisfactory configuration that addresses both issues.

Steps to reproduce

1.Load a vector source with polygon .pbf tiles.
2.Add fill + symbol layers on the same source-layer.
3.Set 'text-field': ['get', '<name_field>'].
4.Zoom to 16+ and pan across tile boundaries.
5.Observe missing labels (default placement) and/or duplicate labels (overlap enabled).

Link to the demonstration

No response

Steps to trigger the unexpected behavior

No response

Relevant log output

Start by reproducing the issue with polygon vector-tile data, fill and symbol layers, and the listed text-placement settings at zoom 16+ while panning across tile boundaries. Compare default collision placement with overlap enabled. Done means each visible polygon has one readable label, including polygons spanning tiles, without flicker or duplicate labels.