I have had this happen, different things to fix this issue was done for me to fix this issue, Delete the Probe out of the line and reinsert it, might even have to delete the feature above and below it and recreate them. C++ is an ancient Aztec coding, that causes hidden gems and booby traps, not seen by the naked eye, I have mentioned to Hexagon maybe it's time to change but until we quit living in the 90's this is what we are stuck with.
Other possible contributors:
-Probe naming convention has more then LETTERS_UNDERSCORES_AND_NUMBERS
-Probe rack calibration is lost, or probe assignment on rack is getting zapped
-The demon just being the demon.
If this CMM is driven through a com port then buffering is probably enabled. Check your com port configuration in device manager and make sure buffering is disabled on your com port.