Typing while the cursor is in a form field results in links interpreting the
input as a command.
reproducible without a .elinks configuration directory, in both xterm and the
visit http://www.google.com/ and attempt to type a search query, for an example
of the bug behavior.
You have to press <enter> before and after typing. It's feature. You can disable
it by Menu -> Setup -> Options Manager -> document.browse.forms.insert_mode = 0.