Are the Broken courier, Oracle engine and dark monastery missions actually the only way to get the silver tercel? 20% drop rate? Can you get it more than once? Someone in my fireteam got it over a year ago, it went to post office, they accidentally deleted it and it never counted in their collections, and it hasn't dropped ever since through a whole lot of missions. Just want to confirm they're on the right track and they just need to be patient with RNG. It's the only thing they're missing from Cursebreaker.