xcode - Score var updates double randomly -

i'm making game, , i'm working on scoring system. however, i'm facing stupid problem. score var when called increase value unary operator (+=) 1, updates value 2 points, instead of 1, , it's doing randomly. have written protocol, i'm conforming gamescene class, , i'm calling method when there contact between sprites.

func wascollected(item: gold) {      score += item.pointvalue } 

could method called twice instead of once? because in console see numbers update sequentially 2 when try collect single point @ random moments. i've tried fix using score++ instead of accessing item.pointvalue property, problem still exists.

here method i'm calling while setting text property in custom class , according breakpoint i'm getting character twice single execution of method. i'm doing wrong? i'm doing method, have bitmap graphics i'm using font numbers.

        var i:nsinteger = 0; < text.length; i++         {              //get character in text current position in loop             //getting scalar encoded value             let scalarencoded:unichar = text.characteratindex(i)             //decoding scalar             let scalardecoded = character(unicodescalar(scalarencoded))             //build texture name character , font name             let texturename:nsstring = "\(fontname)\(scalardecoded)"             print(texturename)              if < children.count             {                 //reuse existing node                 letter = children[i] as! skspritenode                 letter.texture = graphicsatlas.texturenamed(texturename string)                 letter.size = letter.texture!.size()             }             else             {                 //create new node if not exist                 letter = skspritenode(texture: graphicsatlas.texturenamed(texturename string))                 letter.anchorpoint = cgpointzero                 self.addchild(letter)             }             letter.position = pos             pos.x += letter.size.width + letterspacing             totalsize.width = letter.size.width + letterspacing              if totalsize.height < letter.size.height             {                 totalsize.height = letter.size.height             }          }