Hi there, I had the same issue 2 weeks after i bought the IEM. The creaking noise started developing when i switched filters (Black to Blue). A few days later i changed the filters back from Blue to Black. The creaking notices disappeared thereafter. My guess is that I had not placed the filter into the IEM properly and failed to tighten the screw that secures the nozzle properly. I would suggest that you remove the filter and try putting everything into place properly. Make sure that the filter fits into the hole snugly and and that the nozzle is lodged into IEM firmly.
From what you have written, it sounds like the nozzle is not firmly screwed to the IEM. Hopefully this advise help to resolve your issue.