I am getting emails to pre order Icewind Dale: Rime of the Frostmaiden but when I go to try to pre order it, it won't let me... in the marketplace even it says I own everything since I have bought the legendary bundle. Anyway to fix this or is anyone else having this problem?

The email is auto-generated send-to-all. It doesn't take into account what you have bought/pre-ordered.

If the marketplace says you've already got it, then it was included in the legendary bundle and it will be accessible when it releases, September 15th.

I thought the bundles don't include pre-order content?

No idea.

But it's an easy thing to solve. Go to the marketplace entry for the book: https://www.dndbeyond.com/marketplace/adventures/icewind-dale-rime-of-the-frostmaiden

If it says "previously purchased" you have it already and will be unlocked Sept 15th with pre-order bonuses. If it says Add to Cart, you don't have it yet and will need to buy within 24 hours or so, to get any preorder bonuses.