Currently, when clicking at the sort arrows, Magnolia the sort definition applied is not clear at all.

If the sort function can be applied to the tag column at all, it could probably work on an array of tags compiled from the very first visible tag of each item.

(6.2.3dx demo) First click on column header - to sort the items in the ascending order.  Result:

Second click, to sort it in the descending order. Result, which looks OKish in fact:

Third click, to sort it in the ascending order. Result: