Many things don't work in the dedicated server environment compared to launching from the game / FMB. I stopped testing from in-game long ago because of it.
Off the top of my head, the most annoying one's are grouped convoys not pulling trailers, lights/smoke/fire that don't work, wrong waypoint speed on many objects, cargo in trains (actor skins section) and other vehicles that don't show up.
I remember making a ground scenario where supplies needed to make it to a certain area in a certain amount of time. It was somewhere around 30 groups of 6-7 vehicles per this massive convoy all pulling anything from ammunition, fuel, bombs, repair parts etc..
Everything looked good through the FMB. Went to fire it up on the console server and every single trailer that was attached to every single vehicle in the convoy simply fell off and was sitting there along the road while the vehicles all took off on their happy way. Every since then (back in August of last year I believe), I just run it through the console server for everything. It's just not worth it lol.
Related to the cows. Here's a funny video from ATAG_Dutch: