The act of charging warms the batteries, which is why starting with a hot one is much more problematic than a cold one. But, the chemical process of charging is slowed by them being cold, and charging a hot battery too fast can overheat them, causing issues. The only time where a super cold battery is an issue is if you leave it that way in a cold environment. When you drive up to a CCS unit to recharge, the odds are that you've just been driving the car for awhile, and the batteries are warmed by that use and the battery management system in the car...thus, ready to accept a fast charge. The CCS unit may have slowed down for numerous reasons, and only some of them are related to the car...they do get hot on their own, and after pumping out that high current DCV, while the car might have been able to accept it, the CCS unit may have throttled itself down to cool itself off. That's generally more of an issue when it's hot...it's cooling capacity isn't as efficient.
After all, a CCS unit is essentially a smart, high-powered, variable DC power supply...there is some loss in converting from ACV to DCV and that heat needs to be managed whether it's in the CCS unit or the car itself. The reason the i3 is limited to 7.4Kwhr when using an EVSE is for the same issue...the conversion of ACV to DCV creates heat, and that's the maximum they wanted to deal with on the i3.