One of Nintendo's major Switch releases for 2023: Legend of Zelda Tears of the Kingdom was leaked weeks before it went on sale. That was a separate piracy issue and shouldn't have affected Yuzu development.
And it wouldn't have if the Yuzu devs hadn't majorly fucked up. The release versions (both public and patreon) of Yuzu would not properly play the leaked LoZ TotK game, so they *acquired* their own pirated copy so that they could fix their emulator. After they implemented the fixes, they then kept it behind the patreon backer paywall for a period of time, as they did with all of their initial patches.
Nintendo was able to demonstrate that Tropic Haze, the Yuzu developer's incorporated company, made money by specifically patching their emulator to work with a game that wasn't yet released. Legally, they were making money by furthering piracy.
From their, it's anyone's speculation as to what happened. Nintendo was able to get all of their Discord messages and Tropic Haze folded amazingly fast, so it's likely that the devs passed that copy of LoZ TotK around to each other so that they could implement those fixes. It's also likely that they had pirated more than just that game. Regardless, Tropic Haze settlement tells us that they really didn't want to come close to a courtroom.