Bug 433528

SUMMARY
- worked FINE in OpenSuse Leap 15.1 / Plasma 5.12.8, so newly introduced in Leap 15.2 / Plasma 5.18.6


STEPS TO REPRODUCE
1. Move mouse over icons, they "dissappear"
2. move mouse somewhere else, they appear again. 
3. click on invisible/disappeared icon, it will re-appear. 
4. click 2nd time to execute/open

OBSERVED RESULT
Thought at first that there are no rules, maybe a graphics card issue (Intel HD graphics). 
BUT depends on file type:
- .desktop, .sh mostly disappear. not all, no further "rule" known.
- .pdf and all LibreOffice files stay stable

Thought that maybe access rights are triggering issue: no, tried. Also e.g. .png files are mostly dissappearing, so not only executable files.

EXPECTED RESULT
icons should stable and visible

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: openuSUSE Leap 15.2 / Plasma 5.18.6
KDE Plasma Version: Plasma 5.18.6
KDE Frameworks Version: 5.71.0
Qt Version: 5.12.7

ADDITIONAL INFORMATION
openSUSE bug also exists: https://bugzilla.opensuse.org/show_bug.cgi?id=1175797