I was having this problem as well and adding the field to the list view didn't help as per emiliocortina's suggestion.
Due to the issue with @Transient in Xcode 15 Betas I was using the following successfully through Beta 5.
@Attribute(.transient) var isChecked = false
Beta 6 broke a number of things for me, related to defaults and then in Beta 7 those were corrected but the above code didn't compile as .transient was removed. I tried moving back to @Transient macro but it still doesn't update the view correctly. However, I did find that there is a new ephemeral option that has been added which seems to work the same as my earlier .transient. The following change got me up and running again.
@Attribute(.ephemeral) var isChecked = false
Seems like documentation hasn't been updated and there is no reference to this in the release notes either.
Try changing your code to the following and see if this works -- you'll probably need to be running Xcode 15 Beta 7 or higher:
@Attribute(.transient) public var samples: [HKQuantitySample] = []
Let us know how it works!