Had the same problem and took me 10+ hours to find this solution with nothing obvious pointing to structs (ie the "Ensure condition failed error). I wouldn’t use the RefreshAllNodes plugin since it will leave a lot of nodes disconnected when they get refreshed. For some reason the pin option (ie in a “Set members in {YourStructName}” node) will be unchecked and you will have to manually recheck the box and THEN refresh the node for it to compile. If you don’t recheck the box and just refresh the node, the pin will disappear and your nodes will remain unconnected. I learned this the hard way by using ctrl + a to select all the nodes in a graph and realized they weren’t connected anymore.
That being said, this is far from the first issue I’ve had with blueprint structs/enums. What are the alternatives here? Make them in c++?