co2 regulator slowly drifting up

I recently decided to upgrade from a one regulator setup to a dual regulator. I've only used it for a couple of weeks now, but it's been bugging me that the inside regulator (closest to the co2 tank) gradually drifts up to 18psi. The outside regulator (farthest from the co2 tank) stays rock solid, no drift issues at all. I ran a test tonight and shut outlet valve on the malfunctioning regulator and watched it drift up to 18 psi in less than 30 seconds.

I doubt this is normal. My question is, is the inside regulator just busted? Or is there some adjustment that can be done to correct the problem. Both regulators match and the whole deal was bought pre-assembled. The regulator body is made by IMI Cornelius. I haven't managed to find instructions, but then I didn't really think I needed them. I've been kegging for a number of years now and haven't encountered issues with any other regulator.

Unfortunately I can't help, but I am having the same problem. My inside regulator drifts up 5-10 psi. It's rather annoying. I set it to 5, and it's up to 10 the next time I check in on it. I haven't tried dialing it down in hopes it'll stabalize where I want it (nothing's hooked up to it right now), but that might be something worth trying.