News may have an impact on a decision to buy or sell but technical signals may not align. For example, good news may decide a savvy investor to buy, but they will await for confirmation signals. If a sector/index is in free fall, it is usually best to wait.
Unless you have "up to the moment news/squawk" so that you can jump on the trade very quickly.... suggest you forget about "trading the news" altogether. What you've observed as "delayed reaction" to "the" news may not be that at all. Whatever reaction there is to the news, it will be reflected in the charts. You don't need to know "why" when it's time to make the play.
Google post earnings announcement drift. There are a number of academic papers on the subject publically available. Large accounts take time to accumulate a position.
This happens a lot especially for small cap stocks simply because people are not paying attention to them as much. Big blue chips like FB and AAPL move immediately because they are popular stocks with a lot of volume and liquidity. For these small cap stocks most traders won't touch them until they have a certain amount of volume in them to make their trades actually profitable. Hope this helped.
Most likely there's another piece of news that's not yet public or they aren't buying due to the news at all.