On the page https://en.numista.com/catalogue/index.php?e=portugal&st=1-2-47-154-5&cat=y there are multiple listings for “Escudo (1911-2001)” in the list of currencies (also see attached screenshot). The first links to page 17 and the last two both link to page 24, with all three using the “c_portugal64” href fragment.
On the page https://en.numista.com/catalogue/index.php?e=philippines&&st=1-2-47-154-5&cat=y there are multiple listings for “Peso (1857-1967)” in the list of currencies, with the links pointing to different pages, but using the same href fragment.
I imagine this “bug” (I assume this is not intended) occurs on other countries as well, but just came across these two examples.