DefaultAugmentation on DU leads to badly generated type

[GratianPlume]

I fell into a pit. exp: Writting a DU in Liberary1:

[<DefaultAugmentation false>] // focus on it
type Bar =
| Test1 of  int
| Test 2

module Bar =
    let inline  foo x = // focus on "inline" 
         match x with
         | Test1 x -> x
         | Test2 -> 0

and then write code in Liberary2

let foo2 x = Bar.foo x

As foo2 is called, some exception is happend. Because DefaultAugmentation false don't generate property Tag, the inline function foo use _tag for judgment. And when we using Bar.foo in another liberary, the code inline to foo2. It visit _tag, bug it's an internal value...