© Springer Nature Switzerland AG 2020. High-lying isolated neutron resonances have been observed in (formula presented). Analyses of the decay properties utilizing shell-model calculations suggest that they could be interpreted as possible variants of proton core excited states. The spins of these states are likely to be originating from anti-parallel coupling of spins of the (formula presented) neutron and the proton (formula presented) state in the assumed respective core nuclei, (formula presented).