You are right. The
Automatic Spacing help page should be updated to indicate that no spacing is added for an expansion that ends with a command.
Concerning the date and time commands they form a class of their own. This is also reflected by the fact that they have their own menu in the edit|add glossary entry window. So I propose to revert to adding a space if an entry ends with a date or time command.
As you point out, explicitly adding a space does not really solve the problem. The advantage of the spacing added by Automatic Spacing is that it gets automatically undone when you type a punctuation.