I had the same problem the other night in my Dreamfleet B58, they were stuck on 125.13. I tried using FSPAX to switch them also with no success. Angry and out of ideas, I quit. I think it had something to do with Squawkbox, but it was late and I didn't feel like troubleshooting it.
"Labor is prior to, and independent of, capital. Capital is only the fruit of labor, and could never have existed if labor had not first existed. Labor is the superior of capital, and deserves much the higher consideration"