I am also unaware to what causes the market to dump but definitely not the start of a bearish season. This is more of price corrections and this happens all the time so investors should not be much affected with this as the market will always recover after a day or two. And i think while we are having this dip, it will be better to start buying bitcoin and your chosen altcoins while they are becoming cheaper today. This might be a good sign that the market is already near to its market's bullish season because we might see an ATH after this.
All the drama going on in China (Evergrande and other stuff) is playing a role and I think that we can be in for a much larger dip. Nobody can really predict what will happen next (many try and always fail lol), but I am waiting a little bit longer before buying anything.