The meter is probably showing an RMS value and there could be some differences in loading. A scope typically has a higher impedance than a meter.
Note that the two output transistors are acting as a half-wave rectifier. They do not conduct during the sinewave negative half-cycle. The resonant tank is being excited by a series of half-sine pulses. These a re probably closer to squarewave pulses because the transistors are operating at their maximum gain.