Nice to know that the original issue goes away in the latest Beta. Regarding the crash triggered by the access to Item.children, if you can provide a runnable code snippet to demo the issue, I'll take another look. You have mentioned a few classes with inheritance, and so I think it is probably worth mentioning that over-using inheritance may impact your app's performance negatively. Concretely, with today's default store (DefaultStore), all the types in an inheritance hierarchy are persisted with one single table in SQLite. If your inheritance hierarchy has many classes, the table (columns and data) can be quite big, which can slow down the performance of fetching and inserting data. That being said, when adopting SwiftData inheritance, you might examine if that is a right use case. This WWDC25 session(starting from around 4:25) covers this topic a bit. You can take a look, if haven't yet. Best, —— Ziqiao Chen Worldwide Developer Relations.