Sorry to hear you are having the same problem. 3M sent me TWO AP917HD filters and both lasted only 8 days or so. The water was unbelievably clear and it was made more obvious to me when they sent me the AP910 filter (the one without the carbon block that goes with the AP902 kit) and the turbidity has increased noticeably.
However, the pressure has not dropped and it has been over two weeks of normal use.
Chad from 3M said it is most likely the carbon block that is clogging up with particles that are <5 micron. I would think that 3M would have tested this filter properly before selling it. It seems a bit ridiculous that a filter that is supposed to last a year or 100K gallons on municipal water is only lasting 8 days.
The clogging rendered the water pressure useless. It was literally dribbling out even after cranking up the PRV to max (75psi).
So........my options now are rather limited. I do prefer the water filtered for chlorine as you can definitely tell the difference in taste. The water also now makes my kids' hair difficult to brush so it must be the chlorine.
I can either add a chlorine-only granule based filter.....and then deal with having the plumber having to cut into the existing piping.......or just leave it the way it is for now. I will call 3M next week and see if they will send me such a unit for free. Yeah, I know, good luck with that.