When Ben changes “Block” to “Waypoint”, I noticed that his filename also changes automatically. When I do a rename (either by Ctr R 2 x or right clinking - rename), it changes the name in the associated script and the EnemyMovement script, but it does not change the script file name from Block to Waypoint. Perhaps there is a setting for this. If not, it might be worthwhile to point this out to others, to manually rename the script file as well.
I had the same result, but found that if you right-click on the block.cs in VS’s solution explorer and rename it, it also updates the Enemy GameObject in Unity correctly as well… So, not ideal and different to Ben’s method, but it may be just a difference between Windows & Mac versions.
I am finding the exact same thing, and when I try using the alternative that Severn2j suggested even that doesn’t work. I need to rename the script in unity and then rename it within the script itself. Like you I wonder if it is a settings thing.
And Ben has literally just said that in the video…maybe I should try actually watching the whole thing next time 
Its the version of unity your using. im not sure why it was taken out in the newer ones or what ever but it usually works for me when i go into my assets and start the name changing from there