Radical ion pairs generated by photoinduced electron transfer from N,N-dimethyl-1-naphthylamine to benzonitrile in acetonitrile solutions undergo reverse electron transfer to the singlet ground state and to the donor excited triplet state of the parent compounds. Both pathways lead to chemically induced nuclear polarization, but on a short time scale the triplet contribution is hidden in the triplet donor molecules. This leads to unusual CIDNP phases and time dependencies which are unravelled by FT NMR measurements and auxiliary optical studies.