It's happening on release Xcode 13 (13A233), on Monterey Beta 9 in a blank playground for MacOS. If I run the same code in an Xcode iOS Playground, or in a Swift Playground on iPadOS (15.0.1), works just fine. When I run a much more complicated formula as part of an iOS app in the Simulator, it's failing there as well. Bizarre.

Thank you! I just submitted FB9685162. I actually only noticed this because I'm in the process of adopting Swift Numerics and was cross-checking my results. Loving it so far!

quick update, still an issue in dev beta 10

Persists in 12.0.1 RC (21A558)