Avoid stopping of sprite on collision

[kray]

I have a few bugs in my game: http://catchalphabets.tk/

This game is help kids learn the correct order of the alphabets. 
When the dude sprite first collects a letter, i.e. A, it stops for a while and moves back, touching the world boundary. How do I prevent that?

Code:

 this.physics.arcade.overlap(player, letters, this.collectLetter, null, this); collectLetter: function(player,letter) {        this.arr.push(letter.name);        this.check();                letter.kill();    } 

[drhayes]

Just to verify: you're not calling physics.arcade.collide anywhere on the player and the letters group?

 

What does this.check do?

[kray]

No I'm not collide on the players and letters. 
this.check is a function to check if letters are collected in the correct order.