In Better Nether Maps, set the minecraft:the_nether scanHeight to something other than 100 (e.g. 50), and set useMapCreationHeight to false. Make a nether map, and add it to the atlas. You should see the nether map sampled at y=50, as expected. Now set useMapCreationHeight to true, and repeat the task. The nether map will look appropriate to its level, but as soon as you add it to the atlas, it will start displaying the Nether sampled at y=100. Obviously it is unexpected behavior for the map to change this way.
It seems that the Atlas is acting as if it is at y=100 regardless of player location or map metadata. I can see two changes that would fix this issue.
1) (Simpler) Atlas Maps should use the Better Nether Maps config scanHeight to generate its map even when useMapCreationHeight is false, rather than defaulting to y=100.
2) The atlas should use the y-level of the first nether map added to it for all other nether maps.
In Better Nether Maps, set the minecraft:the_nether scanHeight to something other than 100 (e.g. 50), and set useMapCreationHeight to false. Make a nether map, and add it to the atlas. You should see the nether map sampled at y=50, as expected. Now set useMapCreationHeight to true, and repeat the task. The nether map will look appropriate to its level, but as soon as you add it to the atlas, it will start displaying the Nether sampled at y=100. Obviously it is unexpected behavior for the map to change this way.
It seems that the Atlas is acting as if it is at y=100 regardless of player location or map metadata. I can see two changes that would fix this issue.
1) (Simpler) Atlas Maps should use the Better Nether Maps config scanHeight to generate its map even when useMapCreationHeight is false, rather than defaulting to y=100. 2) The atlas should use the y-level of the first nether map added to it for all other nether maps.