Importing pdf substitutes mathematical italic small 𝑡 for random unicode (푡)

I have this PDF here: output.pdf. It has all fonts embedded. However, when trying to open this in Inkscape, it substituted some characters for some Chinese characters. The output can be seen here: output.svg Why is this happening (for what it's worth, this problem also happens on LibreOffice Draw)? I am on Windows 10, with Inkscape 1.0.1.