Is Amazon cancelling preorders?? (here's how NOT to worry)

I've noticed some authors lately saying that Amazon "cancelled" the preorders on their book. (Disclaimer: I have no way of knowing what actually happened, I'm just commenting on what I've seen publicly.)

The way I understand it, this actually cancels all the preorders that had come through before their release date, so authors end up losing out on all that income. What the heck, right?

Tbh, lots of questions went through my head: What is going on? Is this happening a lot? Is this a trend?? SHOULD I BE WORRIED???