Not exactly new16 Jun 2021 11:01
SP decline despite positive developments is as old as the stock market. This is not a new phenomenon.
See a snippet from the article below. It's a broad article, not talking specifically about AIM, cyclicals or growth companies. Have a read.
https://www.investopedia.com/ask/answers/06/stockdeclinegoodnews.asp
There are many possible explanations for a stock's value declining despite good news being released. Oftentimes, investors can discern stock moves based on both the science and art of its valuation. As such, study and awareness of all the possible factors can be important for gauging any potential moves or volatility following good news.
Broadly though, one of the most important things for an investor to do is remain calm and consider both the time frame for your investment and the reason you bought the stock in the first place. Stocks can see a lot of short-term volatility following any new announcements and particularly announcements that are surprisingly good or bad. If a stock holding is part of your long-term portfolio, it can be important to revisit or potentially change your investment thesis with new announcements and developments. If the release of good news remains inline with your investment thesis and a sell off occurs, it just might represent a buying opportunity for you and a chance to add to your long position at a relatively low price rather than selling with the crowd.