GNOME Settings app starts very slowly, gst-plugin-scanner high CPU usage

[Mark]

The GNOME settings application takes very long time to open. Might be caused by gst-plugin-scanner, which exhibits high CPU usage after the Settings app is launched (and until the time it opens).

EDIT: I think I may have narrowed down the issue to graphics drivers. The laptop I'm using is an NVIDIA Optimus laptop. I installed Bumblebee a few minutes ago and the issue seems to be gone (at least as far as I can see for now).

1) The release of Ubuntu you are using

18.04 LTS

2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center

1:3.28.2-0ubuntu0.18.04.1

3) What you expected to happen

Settings application opens almost immediately, no high CPU usage

4) What happened instead

Settings application takes around 20-30 seconds to open, while gst-plugin-scanner hogs the CPU (at the same time).

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gnome-control-center 1:3.28.2-0ubuntu0.18.04.1
ProcVersionSignature: Ubuntu 4.15.0-29.31-generic 4.15.18
Uname: Linux 4.15.0-29-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.3
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Tue Jul 24 00:22:09 2018
InstallationDate: Installed on 2018-04-27 (87 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
SourcePackage: gnome-control-center
UpgradeStatus: No upgrade log present (probably fresh install)