When saving attachment incorrect directory path (/usr/bin) is suggested and I always need to select the proper one (which is for me always the same). The side effect of this suggestion is loading unnecessarily big contents of /usr/bin directory.

Reproducible: Always

Steps to Reproduce:
1. Click on an attachment in mail
2. In dialog click "Save as..."

Actual Results:  
Suggested path is /usr/bin

Expected Results:  
Suggested path should be home folder or last folder I used for saving an attachment.

I used to suffer from this bug: https://bugs.kde.org/show_bug.cgi?id=357557
...where the result of suggesting path file://home/user/ was showing also /usr/bin contents. But after some time it is directly showed /usr/bin.

I also tried to test with clean config (empty home directory) and the first suggestion when saving attachment was a proper home directory one. But maybe after a restart it was back to /usr/bin. Even when I select a home directory to save attachment, then save it and then try to save it again -> /usr/bin is suggested again.

I have Plasma 5.5.4, KF 5.18, KDE Apps 15.12.1, Qt 5.5.1, (KMail 5.1.1)