It does sound like something specifically tied to how the R keybind interacts with build blueprints, since everything else on your setup works fine. From what you described, it’s likely not a hardware problem but more of an input mapping or blueprint reference issue. I noticed a really similar discussion where another user reported the same behavior the R keybind wouldn’t trigger until a blueprint was already active. You might want to check it out here: https://forums.unrealengine.com/t/my-stairs-wont-place-when-i-press-r/2658091