Steps to reproduce: 1) Open Plasma Discover 2) Go to Plasma Addons 3) Watch your memory, but be careful: it won't take long. Bug 387630 looks same, though it says, it was fixed long ago.
It helps, if you click quickly on one of subcategories.
Using KDE Neon, Plasma 5.13.1
I'm sorry, I my Discover package was outdated, because of some version conflicts. I solved them, now its behavior is ok. How can I delete this report?
Thanks for the update; let's close this.