This project exists to reproduce this issue with Mapbox's Compose extensions for Android. To run the project, you will need to add a string resource named mapbox_access_token, in addition to being generally set up to build Mapbox-enabled projects.

When you run the app, you will see a map of the Earth on the top half of the screen, with a white Box() below it. Tap the white box, and its height will be cut in half. You will see the map's scale bar move downward as the MapboxMap() expands, but otherwise the newly-used space is untouched. Notably, map tiles are not rendered there.

This is not tied to the viewport — you can change the center and zoom and get the same results. However, if you change the code to simply remove the Box() instead of changing its height, then the map redraws as expected.