In a low-inductance ablative discharge through a capillary made of polyacetal (POM), lasing on the Balmer-α line of OVIII at 10.24 nm is identified. In line with previous studies of lasing on CVI ions, it is argued to be the consequence of charge exchange collisions after a m=0 instability. Lasing in both cases occurred at about the same time after beginning of the discharge, although lasing on the Balmer-α line of OVIII was less frequently observed, i.e., in approximately one out of ten discharges. Lasing on the CVI ion was seen in one out of three discharges. This is probably due to the need of reaching higher electron temperatures to completely strip oxygen ions simultaneously in the hot constrictions (necks) of the plasma instability.