Weird sound from hermetic compressor

[jayryu]

I checked a reach-in freezer- 2 door, copeland RSN5-0075-IAV, R404a, txv system w/o receiver - due to not enough freezing temperature.
During checkup, I heard weird sound from inside the compressor. The sound was high velocity leaking sound, during the sound occurs the suction pressure moved from 20 psi to 80 psi and the frequency of sounds was every 1 ~ 2 seconds.
I thought the high pressure gas leaked to low side continuously and planned to replace the compressor the next day.
Next day, I tried the freezer power on and found the compressor working fine without any weird sound as like nothing happened a day ago. I am very confused about what was the weird sound. Any gentlemen have the same experience or knowledge?

[Magoo]

Sounds like internal relief letting go, possibly over charged, w/o receiver and with TXV it would be critical charged. Clean condenser, recover system charge and start again and add nameplate system charge