Could not check for software updates! (apt-get code: 126)

whonix 9.6 , tester repository , one of the whonixcheck lines:-

WARNING: Debian Package Update Check Result: Could not check for the software updates! (apt-get code: 126) please manually check: (open a terminal, start menu -> Applications -> System -> Terminal.)

why this message appears ? also there is no one update or upgrade when i check by sudo apt-get update & dist-upgrade?!

AppArmor bug that will be fixed in next testers-only version.