Tested it in test2.

• By rearranging templates via moving them in Transclusion box, I was not able to separate template parameters - e.g. to make {{s-bef|before = [[Leonardo Domenici]]}} --> {{s-bef|before = }}.
  • Also tried the exact steps on https://en.wikipedia.org/wiki/Wikipedia:VisualEditor/Feedback/Archive_2014_1#Add_content_and_other_transclusion_mysteries:

"Example: here all I did was use the "up" button four times: "up" the lowest "content", "up" the lowest s-aft, "up" the lowest "content" again, try to "up" the lowest s-aft again. Result when you want to save it: the s-aft has simply vanished :-)"

It was non-reproducible - either the issue is resolved or I am not inventive enough :( I'd like someone else to take a look at the issue - hence I've assigned some priority to it.