I think your tech confused a few things. The sensor crack occurs sporadically and the cause is officially unknown. The most likely suspect is the layering of the IR filter. It is impossible to miss on your image.
The unnoticed defect is the red line, caused by a dead pixel.
The M9 sensor is still in the Truesense catalog, is the same as for the ME and should be available as a spare for at least ten years after production on the ME stops.
Originally Posted by CameraQuest
I'm told by a Leica tech that some M9 owners have cracked sensors and don't realize it from improperly mounted sensors.
The reason is that the cracks appear as lines in the image often don't show up in smaller size prints.
Check towards the corners of your sensors first, with a magnifier.
Or have a tech check for you.
As these sensors are no longer used in the newer M, getting a cracked M9 sensor replaced now UNDER WARRANTY while replacements are still available takes on new urgency!