Search from a block gives incorrect landing URL, then second search fails

To reproduce this problem:
1) initiate a search for TARGET from the standard search block (Apache Solr is the only search module enabled) in the sidebar on a regular page (not a search page)

2) the url when the search is complete looks like this:

http://MYDOMAIN/search/apachesolr_search/TARGET

and the results are presented on a page that has the search box near the top. (The original search block is not presented)
I don't know where the /apachesolr_search/ part of the URL came from!

3) initiate another search, say for TARGET again

4) this search fails as if there were no search parameter: the search box is empty and the url now looks like this, which I guess is what it should have been all along:

http://MYDOMAIN/search/site/

5) type TARGET into the search box and initiate another search

6) this time the search works, and the url looks like this:

http://MYDOMAIN/search/site/TARGET

I am on Drupal 7.22 with a very recent dev version of Apache Solr Integration: 7.x-1.2+2-dev

Is this a bug or is there something wrong in my configuration?