So the addition of the ExtendedSVG renderer fixes the script already? I've just installed the userscript at https://dbcm.github.io/waze/valfix/valfix.js as a userscript on Firefox, but the validator still doesn't seem to work yet here (I've made it so that the fix gets executed before validator).
I'll look into it later if other people say this does seem to fix validator for them.