I think I have a knack to break things in weird and unexpected ways.
And finally for the win:
[Edit] that localized French error message says "This package is not officially supported by Ubuntu. Please remove any third party package and try again"
Now, I think this happened because I encountered the crashes, could not upload them immediately due to network unavailability, then updated, rebooted and attempted to submit them after that.
Can anyone concur?