The problem comes from here:
i386: libglibmm-2.4-1c2a 2.29.11-0ubuntu1
amd64: libglibmm-2.4-1c2a 2.28.1-1
I downgraded libglibmm-2.4-1c2a from 2.29.11-0ubuntu1 to 2.28.0-1 on i386 and the issue disappear. ubiquity starts correctly with --desktop and no more error in debug.log
amd64 will doubtlessly suffer from the same problem once the build failure is fixed on this arch.
The problem comes from here:
i386: libglibmm-2.4-1c2a 2.29.11-0ubuntu1
amd64: libglibmm-2.4-1c2a 2.28.1-1
I downgraded libglibmm-2.4-1c2a from 2.29.11-0ubuntu1 to 2.28.0-1 on i386 and the issue disappear. ubiquity starts correctly with --desktop and no more error in debug.log
amd64 will doubtlessly suffer from the same problem once the build failure is fixed on this arch.
I added a task for glibmm2.4.