Queries run twice (once on wrong thing) after submitting search block forms on main search page

Here are my notes from debugging that lead to noticing this problem.

why it it looking for "hello" when just search for "something"?
its a search problem, not a d8mi problem

investigate by:
clear watchdog
search for "word"
ok
search for "differentword"
watchdog sees "word" and "differentword"

if search box on search result page
form action is

<form id="search-block-form" class="search-block-form search-box" accept-charset="UTF-8" method="post" action="/d8-git/search/node/658578658765786">

but what we probably want is

<form id="search-block-form" class="search-block-form search-box" accept-charset="UTF-8" method="post" action="/d8-git/search/node">

But if the search block is on another page, we in fact do want

<form id="search-block-form" class="search-block-form search-box" accept-charset="UTF-8" method="post" action="/d8-git/search/node/658578658765786">

The menu callback handler for /search/node/foo should check if the POST contains
form_id=search_block_form
if yes it should prevent a search being made for 'foo' before it actually searches for the string in the POST (which comes from the block).

So if have done
/search/node/foo
and the search being done is in the block search for "bar",

then both a search for "foo" and "bar" happen (see in the watchdog).
The ui looks fine though, the block term is moved to the advanced search form, and the url of the page changes ok to /search/node/bar

This might be related to this 6.x Solr issue #1481326: Queries run twice after submitting search forms on a custom search page
and might be related to this old support request from 2008 that had no resolution http://drupal.org/node/103909 (Strange Search block behavior - have to type search twice to work).