You probably need some power supply decoupling to your oscillator.
Fit a suitable capacitor between 3V3 and ground right at the oscillator, then add a resistor or small choke in the supply line to the oscillator.
The capacitor will then supply the pulsing current demanded by the oscillator and the fluctuations in both ground and 3v3 source will both be diminished.
The size and type of capacitor depends on the operating frequency and supply current of your oscillator, but a 10nF chip capacitor and ferrite bead might be a good place to start at around 65 Mhz.