This is likely caused by the lack of sync of the administrative file when it's updated by update-alternatives. With ext4 it is some possible under some conditions that the file was moved in place before that its content has been written...
I have pushed a fix for this in upstream's git repository: 0e0e26cb8e9e3b8e3a60c329d8ea0c6e5445742c
It will be fixed in Ubuntu the next time we sync dpkg >= 1.16.1.
This is likely caused by the lack of sync of the administrative file when it's updated by update- alternatives. With ext4 it is some possible under some conditions that the file was moved in place before that its content has been written...
I have pushed a fix for this in upstream's git repository: 0e0e26cb8e9e3b8 e3a60c329d8ea0c 6e5445742c
It will be fixed in Ubuntu the next time we sync dpkg >= 1.16.1.