Comment 10 for bug 1334495

Thanks for the additional info. Then we can leave that theory behind.

It was not quite correct when I said that WenQuanYi Zen Hei was the previous default font for Chinese. It was in 13.10 in case of a Chinese locale, but that does not apply to your situation.

The previous package for rendering Chinese, that was previously installed for all users, was fonts-wqy-microhei, and the new replacement is fonts-droid.

http://bazaar.launchpad.net/~kubuntu-dev/ubuntu-seeds/kubuntu.trusty/revision/1265

So let's try to verify that the issue is related to this change: Can you please

1) reinstall fonts-wqy-microhei and

2) uninstall fonts-droid

and let us know if the mixed font problem disappears that way.