Cover doesn't look sealed topic

So I've had my Z3C for nearly a month now and I have been very happy with it except for one thing, the left port cover doesn't seem to sit flush with the body of the phone, it looks like it's not sealed correctly. Pushing it in only results in it returning to its regular position a minute later. I have however gotten the phone wet, but not submerged, but it's still completly fine. I'm just concerned that one day it will fail to seal and I'll have a water damaged Z3C on my hands.