Repro

open System
open System.Threading

let callThrice (action : Action<_>) =
    for i = 0 to 2 do
        action.Invoke ()
        Thread.Sleep 500

let makeHandler () =
    let count = ref 0
    fun () -> printfn "Count: %d" !count
              incr count

let try1 () =
    printfn "try1"
    let handler = makeHandler ()
    callThrice (Action<_> handler)

let try2 () =
    printfn "try2"
    callThrice (Action<_> (makeHandler ()))

try1 ()
try2 ()
printfn "Done"
Console.ReadKey true |> ignore