GeometryReader broken after update

I've downloaded the new Xcode 11.4 update and it's broken my codebase. I use GeometryReader to determine the user's Watch screen size so it can draw a frame that fills up most of the frame.

Say if I wrote this to draw a rectangular frame:

var body: some View {
  GeometryReader {geometry in
       ZStack {
       // Draw rounded rectangle flashcard background

       RoundedRectangle(cornerRadius: 15, style: .continuous)
       .frame(width: geometry.size.width, height: geometry.size.height*0.9) 
        }
     }
 }

It looks fine at the moment. But my main view usually uses subviews more like this:

var body: some View {
    GeometryReader {geometry in
      ZStack {
      // Draw rounded rectangle flashcard background
      
        Frontside(id: self.$settings.randomNum, sheet: self.$showingSheet, rotate: self.$fullRotation, invis: self.$showNextCard, col: self.$colour, width: geometry.size.width*0.9, height: geometry.size.height).environmentObject(self.settings)
        .rotation3DEffect(.degrees(self.showResults ? 180.0 : 0.0), axis: (x: 0.0, y: 1.0, z: 0.0))
        .rotation3DEffect(.degrees(self.fullRotation ? 360.0 : 0.0), axis: (x: 0.0, y: 1.0, z: 0.0))
        .opacity(self.showResults ? 0 : 1)
        .zIndex(self.showResults ? 0 : 1)
        
      }
    }
  }

public struct Frontside: View
{
  @EnvironmentObject var settings: UserSettings
 
  @Binding public var id: Int
  @Binding public var sheet: Bool
  @Binding public var rotate: Bool
  @Binding public var invis: Bool
  @Binding public var col: Int
  public var width: CGFloat
  public var height: CGFloat
 
  public var body: some View
  {
   
    ZStack {
      // Draw rounded rectangle flashcard background
      RoundedRectangle(cornerRadius: 15, style: .continuous)
  
        .frame(width: self.width, height: self.height)
     
        .zIndex(0)
    }
  }
}

For some reason this causes an error when I call Frontside. Does anyone know why? There doesn't seem to be a real difference between the two code snippets other than using a subview in the second example.