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Does that happen with any font? Or is it only a particular font?
Do you see it in Inkscape, or does it only show up after you save as PDF?
Yes, I agree with Moini about needing the SVG and PDF file, and also the font, if it's only a specific font that does it. If you use the Reply button (not Quick Reply) you can attach files to your next message. Or you could upload the files anywhere you like, and give us the link to them.
You could try selecting the text in Inkscape, and click this button, in Object menu > Fill and Stroke > Fill tab
(This is Moini's last suggestion "fill rule".) Then save as PDF.
If that works, then that's a very weirdly made font. (kind of what flamingolady was doing, a while back) But if you're saying this happens with any font, we definitely need to investigate further.