Blocks witth custom geometry render their top face UV as flipped on the Y axis when per-face UV is used. This is inconsistent with entity rendering and does not occur when box UV is used.

Reproduction
1. Download and install the attached addon.
2. Create a world with the attached addon, being sure to enable both the associated resource and behavior pack, as well as the "Holiday Creator Features" experimental toggle.
3. Give the block contained in the addon to the player and place in world via:

give @p geyser_custom:gmdl_1

4. Observe that the held item, which is applies via an attachable, has the expected orientation. Observe that the block placed in the world has its UV flipped on the top face.

Observed Result:

The top face UV of the block is flipped on the Y axis

Expected Result:

The top face UV of the block should not be flipped on the Y axis, as is consistent with the default for entity based models.