Oscillator output voltage levels
It's quite likely that the combination of a 100 MHz oscilloscope bandwidth and the loading capacitance of the x1 probe produce this apparent error in the amplitude of the 24 MHz signal. The 100 MHz bandwidth is quoted as the 3 dB bandwidth so this will cause a perceived amplitude reduction and it is likely that the oscillator module won't be specified with up to 20 pF typical probe capacitance. Try running it with a x10 probe to see if it improves.