When I was playing arena mode today, I found that Defender of Argus just buffed the Fire Elemental on the left but did not buff the totem on the right side. It should be a bug.
https://i.imgur.com/cAsO6Op.pngLooks like a bug indeed, thanks. It would be great to have a full HSreplay if you have an addon which uploads your replays there, or a screenshot as well which highlights the icon on the left showing when you played Defender of Argus to see what it says it did.