Ok so, devils advocate view here. Russians could do this exactly because Spain is on the fence and they would rather they were more antagonistic. They actually want war with Europe, so they can do whatever they like and claim it is Europe's fault for being aggressive. Don't forget, they don't really believe that they are losing the war in Ukraine. They could also be hoping to get Europe embroiled in its own conflicts.

It sounds unreasonable sure, but tbh I am not convinced that the Russian government is reasonable.