When Google launched Instant, the main goal of this feature was to guess your query before you finish typing it and to instantly display the results. This works well if your typing a popular query, but what happens when Google can't autocomplete your query and you're a slow typist? You'll usually see the results for partial queries that include the words you haven't finished typing.
Now Google no longer includes the word you're currently typing if it's not very likely that it's a complete word. If you type [android qualcomm qua], Google will only show the results for [android qualcomm]. When your query becomes [android qualcomm quad], Google no longer ignores the third word. Here's another example:
If you actually want to find the results for a query and Google ignores the last word, you can always press Enter, click the Search button or click "Search instead for ...".