Rick Inman once bubbled...
It's a sealed diaphragm, which the tech guy at DTW said should NOT have a 1st stage freeze issue. Humm...??
"should not" and "will not" are two very different things
Every reg will free flow given the right conditions; it's just that some are less prone than others. I use a Mares Abyys reg, and it has never free flowed. However if I cold soak the reg to temps below freezing and then jump in the water, I have no doubt that all I will see is bubbles after I take my first breath. Absolutely no one can make the claim that XYZ reg is completely incapable of a free flow. Only that it is able to withstand most conditions that can cause one. It is up to you to ensure that you follow some simple protocols when diving in conditions where the air temperature is below freezing.
If you live in an area that has below freezing temps, and still wish to dive this time of year. I highly recommend you sign up for the first Ice Diving course of the season. The things you will learn will be useful in the late fall when the water is still open, but the air is very cold.
This time of year is great, no boats, no algae, and very low probability of inexperienced divers stirring up the bottom. Don't let this time of year pass you up.