Msg#: 4332769 posted 10:49 am on Jun 30, 2011 (gmt 0)
A search for "domain.com keyword" is different from "site:domain.com keyword" as Google would treat the first search as two keyword search giving results for other domains as well that might be relevant to the query while in the later your search for "keyword" would only show results from "domain.com".
Msg#: 4332769 posted 12:17 pm on Jun 30, 2011 (gmt 0)
Considering that "red widgets" and "widgets red" give different results I think it is neither unusual nor unexpected. If the searches are literally as described in the OP then there are two quite distinct arguements which will potentially give different results.