Ok,we have noticed some changes which started on 4/21/15.
We have a product: "redwhite widget"
The correct spelling is "redwhite widget"
The common spelling is "red white widget"
By common I mean that people search for "red white widget" 100 times for every 1 time someone searches for "redwhite widget"
So obviously we have optimized our page for this product to target "red white widget" searches.
Starting on 4/21/15 our page for this product started dropping in the search results for searches for "red white widget".
Now what has me thinking that google changed how they handle search queries is this: We have 2 adwords ad groups, one targeting [red white widget] and one targeting [redwhite widget], both exact match. Every since 4/21/15 searchers searching for "red white widget" are being shown the ad for "redwhite widget". This is reflected both in our results when we search and in our adwords stats for impressions.
Since our ads are exact match targeted, google must be changing the query before processing the search results and ads.