Yep, this is normal. I would suggest that you consider the hints mode to
apply only to the visible links in the current frame, not every link on the
entire page.
If you don't see your link, either scroll a full/half page with <c-d> `<c-f>
<c-u> or <c-b>, or perhaps search with / and then select the url
If you think about it, hinting ALL of the links on a page would be very
heavy, and would spoil the "narrowing down" of links. Lots of websites can
be very large, with MANY links, which would render the feature unusable if
applied to the entire page.
Try pressing f on a reddit comment page, and you'll see just what I mean, haha!
This might be a good opportunity to learn and use some other handy commands
to make navigation more efficient; for example, if you see a link that you
might want to follow, but not yet, "mark" the spot with m followed by any
letter key. This applies only to the specific page, and is remembered for
the session. To go back to it, press apostrophe and followed by the letter
you assigned it to, and you'll return exactly where you were. This mirrors
the same feature on vim; super handy!
:help marks
dactyl://help/marks
:help hints
dactyl://help/hints
Cheers!