Inelastic excitation of Er by a U beam, studied at near-barrier energies, has led to the observation of unusual features in rotational bands built on low-lying vibrations. The population of the high-spin members of the K50, b-vibrational band is enhanced due to mixing with the K52, g-vibrational band at spin 4. Strong mixing of the K50 band with a rotationally aligned 2 qp band results in this ...