Comment 1 for bug 167267

Yup, same thing happened to me. I thought I had lost my mind. I had a Inkscape file using Monterey font that I had downloaded/installed from myfonts and it became a Font Family within Inkscape. But the next time I opened the Inkscape file, the font had changed to some other Handscript font.

As per the instructions above, I opened Control Panel-> Fonts -> File -> Install New Font... browsed to the source font file and over-installed the desired font (in my case Monterey). Then rI e-opened the Inkscape file and the proper font was displayed.