[Strom]

I have a guess, but I haven't actually researched this specific case to be sure.

intoPIX seems to be based in Belgium. I'm not sure exactly what type of patents RED has, but there are types like software patents which don't exist in the EU. Or perhaps it isn't about the type and RED just straight up doesn't have EU patents even if they theoretically could. Combine that with intoPIX (and I haven't verified this) only operating inside the EU, or at least outside of the US. You end up in a situation where RED would have difficulty suing intoPIX, because intoPIX doesn't operate in a jurisdiction where RED holds the relevant patents.

Once Nikon enters the picture, things change. Nikon clearly has US presence.

Of course it could also just be that RED doesn't care about small fish and only started caring now because Nikon has the potential for a lot of revenue.