Conversion checklist items into tasks behave differently, depending on the view that is current when you perform the action.
If you have a project that includes an item with a checklist and you convert this list into tasks, being within the project view then new items will belong to the project. When you do this being in the global Next list then new items are created as standalone items.
Is it conscious behaviour?
I don’t think this is the correct behavior. I’ll create a bug ticket for this.