It's looking more certain that what we've been seeing in our DC is a poor reaction of SP30s to temperatures below about 6°C. We haven't seen any issues with SP10s yet at these temperatures.
Some machines work fine at low temperatures. I've seen a few operate just dandy at intake temperatures as low as 2°C. However, others will show problems at intake temperatures as high as 8°C.
When a machine has trouble at low temperatures, it's often specific ASICs that show the problem (often #2 and #17). It's not always the ASICs in the front that have issues, though it seems more common to be those. Once an ASIC has trouble at low temperatures, it sometimes has trouble even when warmed up. Sometimes it has to be disabled permanently; other times it can be enabled once the machine is warmer.