Demo of a 4 layer footprint with 4 layer no solid regions. PCB must be set to 4 or more layers before placing the footprint. Placing a 4 layer footprint into 2 layer PCB forces the footprint to be Top and Bottom layers only so setting a 2 layer PCB to 4 layers after placing it retains the footprint as Top and Bottom layers only.
The footprint is:
DEMO OF 4 LAYER NO SOLID