Thanks for letting me know, I don't really use the Cycles renderer myself. It's probably something to do with OpenGL access being different when Cycles is active.
6 years ago(+1)
Came across this too when I tried to reproduce the issue. Textures not showing up seems to happen when you start a new scene with Cycles on before using Sprytile. It's a little strange that it continues to work when switching to Cycles after setting up Sprytile, but this issue has been noted in the recent docs update :)