I THINK I remember that on some radios, when you migrate them from ProGrammer to RPM, or at least RPM at some version level, then all the internal formats change and the location of various data gets remapped, and if you don't do the upgrade procedure just right then you will have to reinstall your feature string. I presume you saved your original feature string?
That needs to be the very first thing you do when you get your hands on any Harris radio. Save that feature string! It'll save you having to ask the TAC to research it and tell you what it's supposed to be.
After you have found your original feature string, reload it into the radio using maintenance tools.
Note: I have found that with the current x300 platform, the length of the feature string can change depending on what features have been added to the current feature package. On these radios, the string length is not guaranteed constant.
I THINK that the string changes length when any feature with a feature option number above 40 is added, but I'm not SURE about that. I can state that when I added 47 (Phase II TDMA trunking) to my M5300 and my P7300, the feature strings both got a lot longer.