There were a handful of big mods that were abandoned by their devs and weren't updated when the DLCs came out. Many of those broke even though they only made some simple change. If you notice any mods are broken as you're getting set up again, go to the workshop page for the mod and check the comments for links to other mods that fill the same purpose. Often a good Samaritan will have forked and restored the mod to working order.