Hitting 'O' in Lynx gives you an option about 'Keypad mode' with
three choices. On some web pages (well, I noticed this with RH
bugzilla's query page), you end up with a result where some form
fields have a number but there is no way to enter information into
the form.

Example: load the RH "Query bugzilla" page in Lynx. With keypad
modes "numbers act as arrows" and "links are numbered", look at the
very bottom just before "Query Actions". There is Summary, Description,
URL and space for you to type something in. Now look at those links
with the "keypad mode" option set to "links and form fields are
numbered". You will see link numbers 809-814, but you will have
no way to type anything into the forms. This can be a nuisance when
trying to narrow down searches.

If this explanation is not clear, I have screenshots of the difference
which are a lot clearer, but the files were 60-70k each so I didn't
know whether to include them or not. Say if you want them.

The obvious solution is "don't use that option on that page", yes.
But if Lynx can fix this, that would be even cooler.