Mesa surface mineshafts place cave_air even if mineshaft piece did not place blocks

The bug

Mesa surface mineshafts always cave_air, even if the mineshaft piece did not place any blocks because it would be floating, see

.

How to reproduce

1. Create a world with the following seed

   -9144014475768710727

2. Teleport to the mineshaft

   /teleport -126 90 162

3. Download the attached datapack

1. and place it in the datapacks folder of the world

2. Reload the datapacks

3. Use the provided function to mark cave_air blocks

   /function marcono1234:replace_cave_air