Or the Senators could have just documented it correctly in the original trade. It's a contract to play hockey, not a complex merger and acquisition deal, there's like 4 maybe 5 things to know lol
Pretty inexcusable a team worth 100s of millions of dollars would miss something like that.
In Ottawa's defense, sort of, they were a huge organizational mess at the time. The Dadonov-2-Ducks trade was March, 2022, and the Sens were sold the next year. While all that was going on, the Ottawa GM (can't remember his name) was desperate to turn the team around and save his job (spoiler alert: he didn't).
In retrospect, it was the Good Lord's way to telling McCrimmon "don't trade Dadonov, he's pretty good." But McCrimmon didn't listen and Dadonov went on to be a star for the Stars.