Text insertion in UIViewRepresentable-wrapped UITextField goes haywire after inserting emoji

Folks, I'm trying to understand what I'm missing here. In a SwiftUI project, I've wrapped a UITextView in UIViewRepresentable as a replacement for SwiftUI's TextEditor control, largely so that I can get it to become/resign first responder status.

This minimally-viable example works fine, except for one bug that I can't seem to resolve: if I add an emoji anywhere in that text view, then text insertion goes haywire — wherever I have the cursor, the character typed will be inserted, but then the cursor immediately jumps to the end of the text in the field.

Code Block swift
import SwiftUI
struct WrappedTextView: UIViewRepresentable {
    class Coordinator: NSObject, UITextViewDelegate {
        @Binding var text: String
        var didBecomeFirstResponder: Bool = false
        init(text: Binding<String>) {
            _text = text
        }
        func textViewDidChangeSelection(_ textView: UITextView) {
            DispatchQueue.main.async {
                self.text = textView.text ?? ""
            }
        }
    }
    @Binding var text: String
    var isFirstResponder: Bool = false
    func makeUIView(context: UIViewRepresentableContext<WrappedTextView>) -> UITextView {
        let textView = UITextView()
        textView.delegate = context.coordinator
        return textView
    }
    func makeCoordinator() -> WrappedTextView.Coordinator {
        return Coordinator(text: $text)
    }
    func updateUIView(_ uiView: UIViewType, context: UIViewRepresentableContext<WrappedTextView>) {
        uiView.text = text
        if isFirstResponder && !context.coordinator.didBecomeFirstResponder {
            uiView.becomeFirstResponder()
            context.coordinator.didBecomeFirstResponder = true
        }
    }
}

Credit to this Stack Overflow answer for the above code: https://stackoverflow.com/a/56508132

Can someone help me understand what I'm doing wrong?

There's an example project available here, wrapping both UITextField and UITextView in UIViewRepresentable: https://github.com/AngeloStavrow/WrappedTextInputExample

Code Block swift
func updateUIView(_ uiView: UIViewType, context: UIViewRepresentableContext<WrappedTextView>) {
    if (uiView.text != text) {
        uiView.text = text
    }
    if isFirstResponder && !context.coordinator.didBecomeFirstResponder {
        uiView.becomeFirstResponder()
        context.coordinator.didBecomeFirstResponder = true
    }
}