Well hopefully foma gets you an answer and compensates you for the number of rolls you bought with a replacement.

I think you film was intended to be sold as ultra fine film which is marketed by photowarehouse. They are the low cost leader for cheapest 120 films.

As for possibilities it be could anything. 120 film is cut down from much larger rolls so it's probably not likely that those two areas were not coated properly. Maybe it could be contamination. If there is still a bit of fixer on your reels that area would be a contact point for the film and restrict full development. Who knows. Try the film in another camera and a very clean tank that's been scrubbed with a bit of hot soapy water and fully dried.