The FCR in GM freezes, when the pilot enters the MARK mastermode from NAV and with the FCR in GM. The freeze is recognized by the missing updates to the scan and the radar picture shown and the center-locked antenna azimuth indicator in the bottom of the MFD. See video for clear explanation and the steps to be reproduced. Bug only appears if MARK mastermode is entered from NAV.
KTO and BTO, other theaters not tested
did not occur
The behavior should be exactly like the FCR behaves, if the MARK mastermode is entered from AG mastermode.