includesvg newly generates pfd_tex files every time it is executed

I’m using the svg package and includesvg to include svgs in my document. As I need so escape % signs in my pictures, I need to edit the .pfd_tex files in the svg-inkscape directory (as explained here). This usually worked out as desired but now all files in the svg-inkscape directory are newly generated every time I compile my document and with that, the escaped characters are overwritten every time.
Does someone have an idea of how I could fix that and only generate the .pfd_tex and .pdf files for newly included svgs?