The following applies to both Item Frame and Glow Item Frame entities.

When an item is rotated in an item frame, that rotation is stored in the frame.
Removing the item, and placing it back in, the item will be in the same rotation.

However, if you:

1. Place an item into a frame
2. Rotate the item
3. Remove the item
4. Unload the chunk
5. Reload the chunk

The rotation value is completely lost. This happens in both single-player and server environments, and can be tracked back through at least 1.17

Link to video of this happening.