Deja Dup provides no progress information and hangs

[Cerin]

Ubuntu's default "Backup" application, which I believe is actually DejaDup or Duplicity behind the scenes, is unusable, because it provides no progress information, and appears to either hang or drag the system to halt as it does something. After 6 hours of waiting for the background "duplicity" process to complete, I usually have to kill it so I can use my computer. The process says it's using the "log-fd=N" option to log output, but attempting to read this file descriptor with tail fails.

If you use the "Backup" gui to initiate a backup manually, it will display a small status window, that gives some vague status information, but very intermittently. However, if you schedule a backup, and that backup is due, then as soon as you open this GUI, the backup automatically starts, and an error message is displayed showing a "backup is already running", and it then fails to even give you any status information at all.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: duplicity 0.7.06-2ubuntu2
ProcVersionSignature: Ubuntu 4.4.0-45.66-generic 4.4.21
Uname: Linux 4.4.0-45-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: GNOME
Date: Sun Nov 6 14:19:08 2016
InstallationDate: Installed on 2015-10-20 (382 days ago)
InstallationMedia: Ubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
SourcePackage: duplicity
UpgradeStatus: Upgraded to xenial on 2016-09-16 (51 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Domagoj Tršan (domagoj.trsan)]

This is still happening on Ubuntu 17.10 (duplicity 0.7.12-1ubuntu1, deja-dup 36.3-0ubuntu0.1). It happened a second time in the last month. Deja Dup backup is stucked and it says my last backup was 7 days ago. This makes the app unrealiable to use.
Listing duplicity processes I can see a duplicity proces is running since Jan 27th. I run simple scenario where duplicity backups everything to local disk (no remote backups). I have more than enough disk space for backup.

Since it happens to me often enough, anybody knows how I can help with debugging the issue?