The order of commands matters in any programming language. In which way it matters is normally obvious, but not always. In such a case I'm afraid there's no way around reading the description in the manual. Especially the remarks in fat red letters.

https://zorro-project.com/manual/en/asset.htm

Zorro finds many such bugs, but not all. Although your start date setting makes here no sense, it could be correct under other circumstances, and therefore does not thrown an error.