I have NEVER seen this with ALL of the Atomic regulators I have used, sold, serviced since circa 1998 and continue to us in my dive school. I use strictly sealed first stage of the atomic regulators and this never happened. In fact, in the European market and our market, EMEA region, only the sealed versions are sold here.
Just like any other brand, some technicians aren't vigilant in understanding and following the mfg's service instructions or use the proper tools properly, they mess up the service, even the least complicated parts. Any reasonably trained service technician will know how to service the Atomic very SIMPLE first stages and how to seal it properly, it doesn't require a rocket scientist to do nor is it a brain surgery. One of my Atomic regulators, sealed B2, hasn't been serviced since circa 2012 and it is working like new without any issues at all (I just haven't gotten around to sending it for service yet).
I just can't believe the BS and misinformation and total lack of honesty and understanding in many posts here. I buy and use and continue to use Atomic regulators for their most natural breathing and performance in addition to their incredible reliability and resiliency. No other regulator brand has these Atomic regulator features or comes close in reliability in our experience except SP. If were going to be stuck on an Island, I'd want an Atomic regulator with me, preferably the sealed version (I wouldn't mind a SP regulator either). I would not want any other brand.
(I am not a retailer or associated with Atomic or SP in anyway. I buy my regulators from dealers and/or individuals.)