There is either rezising going on or zooming. If you used it the same way as in the example (a dedicated layer for the trail sprites below the player's layer), make sure the trail's layer has the same settings for zooming/scrolling as the player's layer.
Btw: If framerate is an issue with your game, consider the sprite way, because a Canvas uses much more gpu/cpu power, and you will at least have 4 or 5 of them per trail.
If you can't figure it out, set up an example cap and I'll have a look at what went wrong.