This is a very common fault and is generally caused by having poor machine control, for example not slipping the clutch, and not turning your head to look where you want to go. Most steering faults arise as the result of turning too wide into or out of junctions (swan necking). Depending on the severity, this can be a rider fault or a serious fault.  Poor steering is the sort of fault that will make an examiner look very hard at your ability properly to control a motorcycle. The more closely you are scrutinised the more likely faults will be spotted.