Unexpected Geometry in Water Tile (13/4630/2102) – Includes Extra Detail Beyond Tile Extent

I am happily building using vector tiles provided by Mapbox and converting them to geojson, but I am encountering a weird issue. when I request a water tile, which should be a blank tile, i am getting an unexpected tile back.

For example the water tile at (13, 4630, 2102) fetched using https://api.mapbox.com/v4/mapbox.mapbox-streets-v8/${z}/${x}/${y}.mvt and converted to geojson results in the following GeoJSON:

{"type":"FeatureCollection","features":[{"type":"Feature","geometry":{"type":"Polygon","coordinates":[[[23.554515838623047,65.5234908466135],[23.554515838623047,65.5130337046694],[23.423023223876953,65.5130337046694],[23.423023223876953,65.56747869944311],[23.554515838623047,65.56747869944311],[23.554515838623047,65.5295977989247],[23.543014526367188,65.52918004717498],[23.539581298828125,65.52676228858198],[23.545074462890625,65.52832674620896],[23.554344177246094,65.5273311931237],[23.554515838623047,65.52722896900354],[23.554515838623047,65.52551776662852],[23.548507690429688,65.52235285756382],[23.55297088623047,65.52221060544161],[23.554515838623047,65.5234908466135]],[[23.549880981445312,65.52718896815179],[23.54473114013672,65.52647783165708],[23.546104431152344,65.52505550049119],[23.542327880859375,65.52391757970713],[23.54747772216797,65.52420206455756],[23.546791076660156,65.5249132631082],[23.549537658691406,65.52576667577034],[23.55022430419922,65.52505550049119],[23.549880981445312,65.52718896815179]],[[23.540611267089844,65.52576667577034],[23.538894653320312,65.52434430581914],[23.540611267089844,65.52391757970713],[23.540611267089844,65.52576667577034]],[[23.53923797607422,65.52662006050738],[23.535804748535156,65.52505550049119],[23.537521362304688,65.52462878601511],[23.53923797607422,65.52662006050738]]]},"properties":{}}]}

Which is much more than the expected extent. I also don't think it is simply one zoom level higher because at level 12 the detail on the island wouldn't be as rough.

Expected extent:

For what I'm building this introduces issues when the rough detail overlaps the finer detail I get when actually requesting the tiles overlapping the island. Is this expected behavior, is this an issue with vt2geojson or with the source data, or is there a way to fix this?

Start by reproducing the example request for tile 13/4630/2102 and comparing the returned geometry with the expected tile extent. Trace whether the extra geometry is present in the source vector tile or introduced during vt2geojson conversion; done means identifying the responsible side and documenting or correcting the behavior.