Comment # 1 on bug 1015011 from Neil Rickert

I can confirm this.

I have been using the new "akregator" from plasma 5 (I'll call it "akregator5")
for around 3 weeks (since installing 42.2).  Previously, I used the older
"akregator" (I'll call that "akregator4").

With akregator4, I often found it useful to set it to show only unread topics. 
I did not find the setting for that on akregator5 until yesterday.  So I
managed without that option, though it was a bit less convenient.

I managed to stumble on that setting yesterday.  So I set it to show only
unread topics.  Then I clicked on a feed that had 10 unread topics.  And it
listed them all.  It looked great.

Then I clicked one of those topics.  And everything on the screen disappeared. 
It apparently marked all 10 as having been read.  This is, of course, useless. 
So I won't try that setting again until I hear that it has been fixed.