FTL travel in my books relies on an Alcubierre drive that bends space and time. Travel to a destination at another star system takes a week at minimum due to the accuracy of the FTL jumps and the preceding sub-light travel to the destination which itself takes a few days. (FTL is impossible within a star system). This turns each system into essentially an island in the galaxy, where our interstellar neighbors are at least a week away. FTL communication does not exist, and messages cannot be received or sent while transiting through FTL. Everything must be communicated through FTL comm ships. These comm ships are sent routinely to all systems, some with more priority than others based on demand. They act as a slow internet for the entire galaxy.

The issue is that FTL travel may influence events in the "past". But time is ever flowing backwards at a certain point, it's just that you will know about and event before it happens. This already happens in real life all the time, such as insider trading. And it can create interesting plot points where information you received has already become irrelevant, like in large scale ship to ship battles.

So you receive cargo and messages before they appear to have been sent from an outside observer. But does the outside observer matter at all, or is it just you and the receiver? The main issues are "temporal cheating" with stock trading. But everything is timestamped anyway so they'll know when communication occurs so everything is tracked and local systems can reasonably allow leeway for other temporal discrepancies. Things may be confusing, but in a couple days or weeks, everyone will be caught up to speed on recent events.

With these constraints, even with FTL comm ships, the messages still spread throughout the galaxy like a web, where the closest systems know about information first and the farthest ones learn about it last. This eliminates just about every causality issue by evenly propagating information outwards, simulating light mechanics through FTL.

This also means that it takes days or weeks for the central governing powers to know about certain events and enforce their rule, but I think that enriches my story. For local emergencies, there's always a preordained contingency plan for just about any situation, mitigating the time delay waiting for orders. There's also emergency courier ships for delivering important system-wide or encrypted military communications at higher speeds, but they're only marginally faster than normal ships. Local governors have quite a bit of authority during these dire times.

So, did I solve most or all causality issues here, and if not, which issues could arise?