When I try to do "Stroke to Path" effect on an "A" text with font of "Liberation Sans Narrow", that effect doesn't workk correctly as you see in the image I attached. And also there are so many fonts that effect doesn't work correctly again.

I guess the glyph is to blame : something goes wrong with the top nodes of triangle inside the A letter.

If you turn letter to path, remove all the nodes but the apices of this triangle, it works properly.

It´s probaly this bug here: https://inkscape.org/forums/beyond/errors-with-svg/#c67339