A walk-in freezer!?
Long term storage of film in a deep freeze can induce embrittlement of the emulsion. Among other risks, when the film is released from the chilled environment, moisture can build up and mottle the emulsion. You really need to store it carefully and conscientiously and allow it the time to acclimatise to ambient temperatures. I store my own film at –20C for long term (acknowledging the risks I mentioned) and at normal fridge temperature for short-term, go-to use.