I have the bug here, https://bugs.kde.org/show_bug.cgi?id=241864, which I shouldn't! Reproducible: Always
neon dev stable is not equal to what that gentoo system is. I'd rather have you reopen the other bug for investigation as you are effectively on kf5 master and plasma 5.6.1
I'm not sure I understand. Comment 17 said they were on Plasma 5.7 and I'm on Plasma 5.7 as well. What does it mean to be "effectively on...plasma 5.6.1"?