Temperature can have an effect on things like this. Much like a rifle barrel. Same can be said for what you are wearing.

I shoot with both eyes open... and inside or at night shooting under the lights, I tend to shoot about 2" left of where I do in normal sun light. Maybe I'm moving my head? I don't know. Plenty of times I might just be a bit off on my shooting that day. It happens.

Something definately changed. Whether it is due to bow causes or shooter causes... thats up to you to narrow down... temperature... lighting... clothing... grip.... weight... arrows.... could be a ton of different things.