I have an issue where the final crucible quest starts. My small fleet and spaceport will destroy the cultist ship I can research it with a science ship. However, it shows 15 hp left and will not allow me to use a military ship to research the ship. I am playing without any mods and with a custom-created human empire. When I right-click on the military ships they go back to the starport. I had this issue in 2 games back to back.