This is in scripts/user-setup-encrypted-swap. I suspect that it's specific to the case where you're preseeding ubiquity, because it only happens if user-setup manages to complete before partitioning has finished.
This is in scripts/ user-setup- encrypted- swap. I suspect that it's specific to the case where you're preseeding ubiquity, because it only happens if user-setup manages to complete before partitioning has finished.