Guys, it's important to try and stay civil, please! The OP stated his opinion that the issue is occurring with the Livernois tune, maybe it is with other tuners also. We don't know. Ask them and their views on the matter directly.
Why is better fuel more important to the 13+? The question is, I think, a chicken-and-egg question. Ok, so we "fix" the issue with summer fuel. But is that a "band-aid" (albeit working) solution? Is there a flaw in the 13 PCM programming, or are the sensors being used with different parameters (tighter), or ...? The reason it is important to make the distinction is that, for example, in days of yore, engines designed to run on 87 would start to ping or knock. The common DIY solution was to use a higher-grade gasoline (89, 91, 93, etc), whatever it took to stop that ping/knock. Rather than actually fix the problem, which might be dirty carb/FI, or valves or timing belt etc. One simple test is for the owner to run a known good fuel in the wintertime as many have suggested, to see if the problem disappears. Maybe a VP/racing fuel even. We can all chip in and help fund this type of test. Stock tune vs aftermaket tune. We still won't directly know how the PCM is handling the data flow, though.
The tunes are hard to fault, but no vendor is infallible, "learning" experiences are inevitable. Asking questions, pushing boundaries is what we are all here for. Sometimes we will find an answer, sometimes we won't. And that's OK.
) as it ignites. Could be plugs, could be injectors. At least plugs are relatively easy to check.