Comment 13 for bug 1630765

Sorry, I missed the reference for the bug report but the fix now landed in zesty and xenial-overlay.

https://lists.ubuntu.com/archives/zesty-changes/2016-October/000050.html

Version 5.6.1+dfsg-3ubuntu7~2:

  * debian/patches/Stop-unloading-plugins-in-QPluginLoader-and-QFactory.patch:
    - Backport from Qt 5.8.

It seems upstream will introduce the same change, possibly as opt-in in 5.6.3 and the default in 5.6.4 as per most recent discussions: http://lists.qt-project.org/pipermail/development/2016-October/027519.html