/hreflang-errors.html
declares this page as its French alternate, but this page does NOT have a
hreflang="en"
tag pointing back to it. The cluster is broken — Google may ignore both pages.
hreflang="fr_CA"
uses an underscore instead of a hyphen.
BCP 47 requires fr-CA.
Cette page est la version française. Elle devrait pointer vers la version anglaise via un tag hreflang réciproque.
A correct implementation would include:
<link rel="alternate" hreflang="fr" href="...hreflang-fr.html">
<link rel="alternate" hreflang="en" href="...hreflang-errors.html">
<link rel="alternate" hreflang="x-default" href="...hreflang-errors.html">