Try the G2 by itself. Not in any loop. Not in series with anything.
Determine if it is a build issue. If there is no noise then try adding just a compressor, no loop or series of pedals.
Obviously a compressor acts very similar to a boost pedal (it boosts the lower output while squashing the higher). If you have noise in the G2 pedal to start with the compressor will amplify it. Then try adding the compressor after the G2. Again no loop or other chains.
Then make a determination if it is the G2, G2 + compressor in tandem or the Helix Loop.