I don't know about the Spanish one, but the Croatian one caused a lot of controversy both internally and externally because it was took over by extremely conservative (and sometimes blatantly pro-faschist) group of mods, to the point where a Minister of Education discouraged students of using it as a source.
funny to think that, back at college (circa 2003) , when wikipedia was still a relatively new and scary things for academics, we were actively discouraged from using it as a reference for information, let alone a source to cite