Watts 263A Problem

I have a 2 stage filter right after the regulator so the water that goes through it isn't filtered. My first filter is a particulate filter and the second is charcoal. Both are 1 micron. The regulator is never outside when it freezes and it has worked perfectly for almost 8 years other than I cleaned it and installed a repair kit 3 three times over the years when it was just a bit off maintaining the set pressure. Flow has always been great and I set my pressure at 55psi. Just normal wear and tear, except this last time the kit and new parts didn't help. There is high silt content where I spend my summers, but I'm only there 4 months/year. I'm thinking I missed something in the cleaning and I'm going to take it apart and try again. I do use CLR to break down the buildup whatever it is.

The new 263A is working perfectly so I obviously missed something in the cleaning/kit install with my old one.

Thank you for your help.