I think that this bug report merge three different issues:
1. Technical. If a child task has no due date and you add a parent with a due date then remove the parent, the child should continue to have no due date (even if it had a due date when it had a parent). I think GTG got it right but, else, it's a bug that should be fixed.
2. UX. It's not possible to know if a due date is inherited or not, hence leading to frustration when trying to change a due date which is, in fact, inherited. Some UI work is needed.
3. Conceptual. Here again, I think that GTG got it right and the reporter has it wrong. There's no way you could possibly change the due date of a child to something later than its parent.
I think that this bug report merge three different issues:
1. Technical. If a child task has no due date and you add a parent with a due date then remove the parent, the child should continue to have no due date (even if it had a due date when it had a parent). I think GTG got it right but, else, it's a bug that should be fixed.
2. UX. It's not possible to know if a due date is inherited or not, hence leading to frustration when trying to change a due date which is, in fact, inherited. Some UI work is needed.
3. Conceptual. Here again, I think that GTG got it right and the reporter has it wrong. There's no way you could possibly change the due date of a child to something later than its parent.