I play exclusively random maps and sometimes certain spells are not researchable but only on some games; then other spells are not researchable on other games. I always use the same template, which I’ve checked to ensure that no spells are banned. Sometimes it’s Force Field, sometimes its Resurrection, sometimes it’s Dimension Door. Restarting a new game using the same template resolves the problem but sometimes introduces completely different spells that cannot be researched. All of these spells can, however, sometimes be found in different towns of the same type. I’m certain that I’m not just having bad luck because at one point I added large amounts of resources, and spent 15 minutes advancing game turns and doing nothing but research.
