It works but the version you installed hasn’t fixed that bug. PR to fix it.
What’s more, that is the 1st version of the portrait expansion. Latest version is much more powerful.
2nd version: [FE7] My New Portrait System That Supports A Full 96x80 or 80x96 box
3rd version: Enhanced Portrait Format Support for GBAFE
4th version: https://youtu.be/s4bXkgEQP74 Tool