The dyansauri tend to be at war with the elves and high elves, and they all come to trade at the same time. I mean, I like the free stuff they leave, but my depot gets covered in giant beetle vomit and I don't want to make everybody siege me at once. Perhaps the dyansauri's season could change.
Yeah I get this too, except more often with the Vamari and the Frost Giants. I mean, I expect caravans to be in danger - I get flooded by ambushes and sieges and many caravans don't make it 3 steps alive, that's part of the unique challenge of CivForge, but there
are things you can do to try and get caravans safely to your trade depot. But what can you do when you've gone through all that effort to get a couple caravans inside safely, and they decide to butcher each other on the depot itself? It's a bit frustrating, sure you get their stuff for free, but it spoils the chance to have a healthy trading relationship with about half the caravans.
I've experimented with some crude workarounds involving multiple trade depots and locked doors, by the way. It's tough to pull off, sometimes they insist on using the same trade depot even if you cut one side off from it and have a second one they can access, and if any traders or animals get killed, or if they merely get frightened away from the depot after starting to unpack, it seems to bug any trading that season ("no traders present" even after any that still live arrive at/return to the depot). I usually have to settle for trading with one caravan while keeping the other safely locked out. DF just wasn't intended to have caravans hostile to each other, I think.
Edit: Not meant to be a rant though, I do love the mod, and the variety of races to fight/trade with is one of its many high points. Just want to emphasize that this is a problem, it makes it hard to actually enjoy the aforementioned variety of races to trade with. ..Conflicts among ambushes of different races, on the other hand, are hilarious and don't really stop me from interacting with them in the intended way (i.e. killing them).