Nemo getting stuck on thumbnail generation for updated files

Nemo on Ubuntu 14.04.4 LTS

If an image file is written slowly (like beeing downloaded), nemo sometimes get stuck on thumbnailing it. It permamnently consumes some CPU cycles then and doesn't open any files anymore.

What happens:
-I download an JPEG image file to the desktop
-nemo shows an "jpeg" icon with a clock dial on it while the file is growing
-After the download is finished, nemo still shows the clock dial
-CPU usage is 10-20% for nemo now
-If further files are downloaded, they may get stuck too and constant CPU usage increase sometimes. Memory usage increases too.
-nemo will not react to double click on any desktop file anymore nor to the "open" or "open with" context menu options for ANY file
-nemo has to be killed and restarted to be able to launch files again.

Notice this may also happen sometimes if the file is written by an application, like saving a JPEG with gimp to the desktop or any folder with an open nemo window.

Some files also always exhibit this behaviour, eg. even when moved to an open folder.

This is a serious flaw, as most users will not identify the problem and will be forced to restart the computer to make "open" work again.
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ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
CurrentDesktop: Unity
DistroRelease: Ubuntu 14.04
EcryptfsInUse: Yes
InstallationDate: Installed on 2015-11-22 (159 days ago)
InstallationMedia: Ubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
Package: nemo 1.8.4-1.1
PackageArchitecture: amd64
ProcVersionSignature: Ubuntu 3.19.0-58.64~14.04.1-generic 3.19.8-ckt16
Tags: third-party-packages trusty
Uname: Linux 3.19.0-58-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm bumblebee cdrom dialout dip lpadmin plugdev sambashare sudo
_MarkForUpload: True