Traktor Pro 2 Issue

Its not 100% percent clear exactly what you mean but I believe those ‘white lines’ are your beat markers for the beat grid. It sounds like you may have the snap or quantize function/s active. You will notice that just under the main volume knob (in the global section) that there is an S and a Q button. This is for snap and quantize. Switch these off and try again. I think this is your issue.