I also have this issue. I did discover that if you put empty .onChange before the sheet, it works.
Button(action: {
planActivitySheetVisible.toggle()
}, label: {
Image(systemName: "plus")
})
// I need this for some reason to make the sheet present consistently
.onChange(of: planActivitySheetVisible) { }
.sheet(isPresented: $planActivitySheetVisible) {
PlanActivityView( )
}