5-bladed propellers are skipped in the blade count slider

This is likely an oversight, but propellers with 5 blades cannot be accessed normally. If you use the slider to set blade count and keep an eye on the number, you will notice that after 4 it skips 5 and goes straight to 6.
5-bladed props should work normally (though i haven't tried them) if you change it via the hidden property editor, so there's no reason for them to be skipped unless they are the cause of an unknown bug which hasn't been faced by me yet.