Those graphs make assumptions, for all you know the FTL trasmission could be able to just send the information to the closest absolute current frame time of all reference frames irregardless to the varying granurality caused by velocity/mass.
I bet a FTL radio would have silly issues like hearing people speaking at a slower rate in virtue of being subject to heavier velocity/masses, or faster in the opposite case.
I mean, why would a FTL transmission need adhere to relativity? We're linking two points in absolute terms, points which are likely to have different flows of time.
Relativity is great to calculate effects that happen in relative terms, which is the only thing we can measure. But in absolute terms... who the fuck knows what's happening there, is there a fucking universal clock tick causing time as a side effect? How the fuck does it work? We can't even test it since we're inside the system and can only experience the relative side.
Also, if the FTL mean of trasmission involved entanglement, how the fuck would the delayed quantum eraser effect play into the equation. Wouldn't it just prevent any violation as it already does?