This might not be your problem. But I spend 3 hours on a problem exactly like this last night. And re-built an example line by line until I learned: Foreach in a picker does not work with the old code I had copy/pasted using @Environment(\.presentationMode) var presentationMode Let me say it again because it's so crazy to me. Simply Declaring that variable, and not using it, breaks picker+forEach's. Which means it has nothing to do with any index you as a developer explicitly used. Ref: https://developer.apple.com/documentation/swiftui/presentationmode. I was able to easily reproduce the following crash when navigating between two views: Swift/ContiguousArrayBuffer.swift:600: Fatal error: Index out of range Instead replacing it with "https://developer.apple.com/documentation/swiftui/environmentvalues/ispresented". Or in my case I was able to do the navigation ( a submit/cancel form ) in a different/standard way Dear Apple, Tried in xcode 5.2 and 5.3, please add a massive deprecation warning when people attempt to use that code.