It is not strange - it is abnormal as was indicated in the first thread you posted re his condition. Black spots abnormal. Shedding so frequently, abnormal. Four weeks later, it continues. Get him to a vet who is familiar with amphibians. I'll go out on a limb and speculate that this is pathogen induced secondary to improper husbandry. Where I've seen/heard of this occuring in tigers, it is often associated with a wet/overly moist environment with improper ventilation i.e., stagnant, humid environment.
You've been given several links regarding proper care of tigers in general and these black spots in particular...have you read these? Should you have read them, I would question why you are feeding feeder fish? This is not something tigers eat...they are fossorial animals. Reread the links you were given re proper diet...and here is another article on food items for caudates you might want to review - note the commentary on feeder fish:
Caudata Culture Articles - Food Items for Captive Caudates