cured calabrese sopressata

A couple of things are likely going on. Twenty five years of success and suddenly things are going sideways-Something in your process or materials must have changed.

What are you using for casing? 2 1/2" beef middles are best- Have you changed casing to fibrous or collagen in last 3 years. Especially so early on it is unlikely that it is case hardening.
This almost sounds like the membrane is not permeable and the gases and moisture are being trapped.
Were they well soaked dependant on type?
Were the casings well pricked to encourage moisture and gas release?

I am not concerned with your spices, but curious as to salt %-type of sugar and %-type of cure and dosage.
Was a starter culture used? What type and dose?

If a starter was used, Did you incubate high humidity-90% RH above 28c for 15-20 hours before taking to the cold room?.
Is there a cross breeze or any ventilation in your cold room?

Your cold room temps indeed seem quite low if using a starter-
For aging-I have best success with 10C-12C and 55% to 65% RH

I usually press for 5-7 days after a week of aging. This usually corrects the shape and provides uniformity