Hello there!
Another Blender 4.1 change.
In the Geo Nodes course, section 4, Tree Generator, the Rotate Euler node is used. Blender flags this node as deprecated.
@StephenWoods
Rotate Rotation does the same job. Set it to local and the result is the same.
https://docs.blender.org/manual/en/4.1/modeling/geometry_nodes/utilities/rotation/rotate_rotation.html#bpy-types-functionnoderotaterotation
Cheers,
Ray