UIPanGestureRecognizer not behaving as expected - sprite-kit

Question

The following code is being used to change the colour of sprites as my finger pans over them. It works but the sprites only change colour after the gesture has ended. Eg I start by panning over the sprites and draw a shape - nothing changes as I pan - then I lift my finger and the sprites change colour.
the print statements are reporting the correct sprite names and all the print statements are being triggered... but the sprite colour change isn't... until the end.
Its confusing me so I am hoping someone can explain.
#objc func drawingpan(_ recognizer: UIPanGestureRecognizer) {
recognizer.minimumNumberOfTouches = 1
if recognizer.state == .began {
print("drawingbegan")
var touchLocation = recognizer.location(in: recognizer.view)
var touchLocation2 = self.convertPoint(fromView: touchLocation)
let nn = nodes(at: touchLocation2)
if nn.count > 0 {
if let dotSpriteTapped = nn.first! as? SKSpriteNode {
print("touchebeganpan",dotSpriteTapped.name)
for spritesquare in MyVariables.allsprites {
if dotSpriteTapped.name == spritesquare.name {
print("changecolorpan",dotSpriteTapped.name)
spritesquare.color = UIColor.red
}
}}
}
}
} else if recognizer.state == .changed {
print("touchechangedx")
var touchLocation = recognizer.location(in: recognizer.view)
var touchLocation2 = self.convertPoint(fromView: touchLocation)
let nn = nodes(at: touchLocation2)
if nn.count > 0 {
if let dotSpriteTapped = nn.first! as? SKSpriteNode {
for spritesquare in MyVariables.allsprites {
if dotSpriteTapped.name == spritesquare.name {
print("namesmatch",dotSpriteTapped.name)
spritesquare.color = UIColor.red
}
}}
}
}
} else if recognizer.state == .ended {
//recognizer.cancelsTouchesInView = false
}}