Hello,
I have been using Inkscape on typesetting for a while now, and I ran into this issue today.
In my svg file, I have pictures applied with filter effects, as well as texts.
However, when I output the file in PDF with "rasterize filter effects" checked in order to maintain the filter effects, I found that some of the text has been rasterized too.
This is weird, considering
1) I didn't apply any filter effects on the texts, and
2) Only some of the texts are rasterized.
Specifically, I have used CJK fonts cwTeX Q Ming and Noto Sans CJK, both in regular font weight, but only the former one will be rasterized with the option checked.
With regards to English fonts, Century Gothic Bold are rasterized, while Century Gothic Regular not.

Much to my disappointment, both "Convert text to paths" option in PDF output dialog, and "Path -> Object to path" beforehand does no work at all.
The texts, despite that they are already paths, will still be rasterized.

I am using Inkscape 0.92.2 (2017-08-06) on Windows 10.
Does any one know the cause of the issue? Or any way to have both the filter effects and embedded texts in a pdf file?
Thanks in advance.

Can you share a file? Maybe we can find the reason when we can examine it.