No Casus belli, for anyone

Playing my first Hive Mind game and i tried declaring war on someone. No war causes. I claimed most of their systems that were visible and have terrible relations, despite this i have no Casus Belli. Checked other empires and saw that nobody had ANY Casus Belli's on anyone else. Anyone else had this issue? Mods being run are Gigastructures, Better performance and Utilities, and UI overhaul dynamic