[singular]

Try typing 'F#', the instant results are irrelevant to F# the language (probably due to the # symbol), but when you click search they become relevant.

I would prefer it to be consistent :)

[ithkuil]

This happens because the "instant" search results are basically precomputed search results of the "first suggestion".

When you type "F#" google search is actually suggesting you "f to c" and the results is displayed accordingly.

It seems that google is not simply executing the partial search as you type (it would be too expensive even for them)

See http://news.ycombinator.com/item?id=1674707