Hi Chris,
Welcome to the forum! I can see why this is frustrating. Usually this type of event is related to some form of transient. I think that the data output relative to the CMR setting is coincidental, although interesting.
Can you send me some more detail as to fclk and SCLK speeds? Can you re-write the proper configuration without resetting the device? Is this the only register that has this issue? Do you see any other failure conditions?
Best regards,
Bob B