This is correct. PBE is developed for total energy of solids, i.e. ground state properties and not the bandgap. There is no rule how large the error in band gap is.
However, it will give you the correct workfunction. In cases where it is the valence band which is important for the conduction, it might therefore give a good description of the electron transport. If it is the valence band which is important you can use the +U correction, MetaGGA or a fitted tight binding model.
