I tried to change certain data entries from the first screenshot to the second (essentially adding Canadian English translation as well as "artist" as an alias. Unfortunately, I get this weird bug that that says "Property P161 already has label "intèrpitri" associated with language code scn." There is no label "interpriti" on this property, so I don't see how it could conflict with other properties.
On second inspection, I figured out that this bug happens whenever I try to change any of the en-ca or en-simple parameters. It also happens when I try to add "artist" to the alias parameter of en.
there isn't supposed to be two properties with the same label in a given language. the bug had allowed that to happen, but is fixed now and now the constraint is enforced.
side effect is that we need to fix the conflicts where they exist. It's not great that unrelated labels can't be saved right now without fixing the conflict but fixing it is probably the easiest thing to do in this case. :/
either https://www.wikidata.org/wiki/Property:P161?uselang=scn or https://www.wikidata.org/wiki/Property:P175?uselang=scn needs to be changed to something else.
Peppepz added one of the labels so he/she might have an idea of an alternative.
Thanks for the report. As aude said there should not be two properties with the same label/alias. We're working on fixing the situation where those could get into the system in the first place so in the future this should not happen again.