I have come across some unexpected behaviour when using the SpriteKit Scene Editor, and wonder if anyone else is having the same issue.
I created a sprite in a scene
I asked a similar question just the other day: XCode 9: SKEditorReference doesn't allow animations?
The only way I was able to get this to work was to put the isPaused on the exact sprite node I was trying to animate (within a ref node - I had created an entire sks scene/file and drag-dropped that into my main scene).
I tried isPaused=false at the top level, main scene didMove to view to no effect, and then added isPaused=false to the main reference node, to no effect. It worked only when I added isPaused=false the actual sprite I was trying to animate. I removed isPaused=false from the the main & ref nodes, and as long as it was still on the sprite node (within the ref node) I was trying to animate: success.
Bottom line seems to be that isPaused=false is required on any sprites within a reference node.