I have disabled akregator-tray setting. When I close akregator, many a time akregator is still running and can be seen in ps -ef output. When this happens, I cannot launch akregator again, unless I will the running instance first. The system panel, tray or any desktop has no akregator window or icon. It is totally in background, nowhere to be seen. It is very irritating to hunt and kill it almost every time. It has been the case for quite some time now, almost 6-8 months. I am running akregator 4.14.10 from archlinux packages. That version is not listed in the version listbox, while filing the bug.
This bug has never been confirmed for a Kontact version that is based on KDE Frameworks, except possibly a Technology Preview version 5.0.x. Those versions differ significantly from the old 4.x series. Therefore, I plan to close it in around two or three months. In the meantime, it is set to WAITINGFORINFO to give reporters the opportunity to check if it is still valid. As soon as someone confirms it for a recent version (at least 5.1, ideally even more recent), I'll gladly reopen it. Please understand that we lack the manpower to triage bugs reported for versions almost two years beyond their end of life.
Just as announced in my last comment, I close this bug. If you encounter it again in a recent version (at least 5.1 aka 15.12; preferably much more recent), please open a new one unless it already exists. Thank you for all your input.