I think CUW has a point in that there probably is no point in a chamber test since it has been under several times without incident.
I was curious about the white specks if they were a factor or not. They are remarkable in that it could be evidence of poor maintenance or neglect. Not necessarily by you but by different circumstances unique to that housing's experience - rinse tank, boatman etc. I saw a housing come up with a what looked like an oil slick on its dome once. The resort staff had rinsed it in the tank intended for wetsuits. Could have been insect repellent, sun block or other lotion. Anyway, point being that whatever it was/is that cause the specks were either a one time occurrence (hopefully it is in this case) or is/might actually be part of your routine.
can you post a photo of the inside of the door showing the inside of the lip that mates against the groove on the main body? Also a picture looking straight down into the groove would be very helpful.
If any further investigation fails to identify the cause of the white specks, at least you might monitor it and see if it gets worse.
I would not pursue any warranty claims. i think that would be a waste of time. rather spend the effort in finding out what if any adjustment you need to make to avoid or eliminate these things from happening in the future.
The good news actually is that you have dived it several times without incident.