Antarctic land/water inconsistencies between neighboring zoom levels

Hello there!!

On the Antarctic Coast somewhat near Matienzo Base, as you zoom in, what was previously shown as open ocean is then rendered as "earth" instead of water. In short, the "earth" type is inconsistent between zoom levels in this area.

I became aware of this bug while developing a citizen science app of orcas using the Protomaps API where it's necessary to be able to distinguish between land and sea in these areas. I was able to reproduce the bug from within the Protomaps demo tile bucket. I screenshotted this demo bucket instead for this issue since it might be more informative.

After more research, I think it's due to using Natural Earth at further out zooms and OSM at closer ones.

Location
https://pmtiles.io/#url=https%3A%2F%2Fdemo-bucket.protomaps.com%2Fv4.pmtiles&map=6.37/-67.391/-63.314&showTileBoundaries=true
https://www.google.com/maps/@-66.3711517,-60.2786988,7.4z?entry=ttu&g_ep=EgoyMDI2MDUxMi4wIKXMDSoASAFQAw%3D%3D

Screenshots
At farther out zooms, Antarctica land has more water around this area:

As you zoom in closer, a huge body of land comes in:

Required information
In our app it's:

• Browser: Chrome on macOS
• Renderer version: MapLibre GL JS 5.22.0
• Tileset version and source:
  • Protomaps API: https://api.protomaps.com/tiles/v4/{z}/{x}/{y}.mvt
  • Tileset: Protomaps basemaps v4
• Style JSON or NPM version:
  • Maputnik altered verison of the Protomaps light theme, style@5.7.0 flavor@light lang@en

Reproduce the discrepancy in the linked Protomaps demo tile bucket near Matienzo Base, comparing the same area across neighboring zoom levels. Read how the basemap combines Natural Earth at farther zooms with OpenStreetMap at closer zooms, then verify that the resulting tiles consistently classify the Antarctic area as land or water.