This just happened on hashinshin's stream
https://clips.twitch.tv/SmallSoftSquidKevinTurtle
The eternal reveals that aphelios was on the dragon. Since there are no assist icons on the dragon kill popup i presume that it was not in vision. But the eternal reveals that aphelios was assisting at dragon.
I can't tell for sure with map cover, but assuming hash's team actually had no vision this makes eternals a literal disadvantage to own.
EDIT: Hashinshin's team had vision of aphelios, but no vision of dragon, which is why the eternal showed up but there were no assist markers.
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