Clicking (left or middle) on some article links, whether in "feed summary" or "load full page" article viewer mode, has no effect -- does not open internally or externally (i.e. firefox). Right-clicking the SAME LINK and selecting an option to open in tab/external browser/etc. DOES work, however.
Other links in the same article work normally. I.e. in "feed summary" viewing mode, the "Complete Story" link seems to always work, although I don't believe that link to be part of the article proper and is generated by Akregator.
Looks like this bug: https://bugreports.qt.io/browse/QTBUG-67870
As described at: https://blogs.kde.org/2018/07/24/2018-toulouse-pim-sprint-report
(look for Investigated Qt 5.11 bug which broke clicking on links in KMail... fixed)