i have the same issue.
If the product open as single product and add to cart.
All variation are added to cart, but if add to cart from bundle product only add the variation which we define the price.
For demo please have a look into a simple example on our website.
Bundle product:
https://in-hq.com/shop/product/graduation-2020-v1/
Single product:
https://in-hq.com/shop/product/t-shirt-v1/
Add to cart both and check, bundle product is not displaying color and size. and single product if add to cart the color and size is displaying.
Your quick action is highly required to elaborate the work.
Thanks
