Every decade i buy new regs as manufacturing moves on . After successfully turning my brother in law to the Dark Side (diving) 8 am looking at new gear. But before i wander out and spend $1000+ on regs i have a question to the Dark Masters of diving( you guys) . Last saturday during a shore dive I experienced my first ever issue with my Mk25/s600/r380 setup after 10 years. ( yes i got them regularily serviced ) Dive started normally - 2500psi fill - no issues. 30 min later @20ft i noticed the contents gauge was dropping visibly with every breath , then rebounding back to its actual pressure. Yes warning bells were ringing..... Below 1000psi the dive became impossible unless you liked 1/2 breaths. Back at 12ft i wasnt worried. Sitting at 12ft i removed my tank/BC much to the horror of my Freshly minted PADI open water partner. I noticed the first stage main spring opening violently with inhalations - looked normal - but just no flow . (please note i did have perfectly working5lt pony with me). Small slow bubbles were escaping from the first stage from the spring area. The regs did the same on the surface later -short stroking. Afterwards during cleanup at home i tried them without getting the problem . I did notice the regs now slowly degass for about 10seconds after taking them off the tank. Back for a service i know - but what is the first stage doing wrong?