I took a peek and it looks like the hover color is making it a bit hard to see the text, however I was able to select and edit it just fine:
Since your links are nested within a Symbol, you’ll need to double click to start editing the content, then double click to enter the Link Block element, and finally double click a third time (or drag select) to highlight the text within it.
To make it a bit easier to see the text inside, I’d edit the hover state of the Link Block to also change the text color to something lighter:
