Problem decompiling F# binaries

I have an F# executable that I am inspecting using Reflector 8.2 (I am using .Net 4.5). I have selected the F# option. When I select a function (I have very few methods), right click and selecting "Decompile' appears to do nothing, but something that looks like F# appears on the right hand side but completely devoid of any identifiers used in the function. In fact it appears to unfold all the local lets! Below is an example:
Given

let mkRewriteRules vars_to_rename_as_terms =
      let ext = (gensym EXT)                  
      let renamed_vars_as_terms = List.map (fun (ID s)-> ID(s+ext)) vars_to_rename_as_terms
      List.zip vars_to_rename_as_terms renamed_vars_as_terms

I see on the right hand side:

let rec mkRewriteRules vars_to_rename_as_terms  = 
        let temporary1 = 
            let temporary2 = (* Statement type not handled *)
            match temporary2 with
            | Some _ as x -> x
            | None -> 
                let ext = Concat _ ToString 
                let temporary3 = Some(Zip vars_to_rename_as_terms List.map   vars_to_rename_as_terms)
                temporary3
            match temporary1 with
            | Some x -> x
            | None -> failwith "Expected non-unit return"

Is this an artifact of how the F# compiler generates, or is there some information missing that might help it do a better job (I know there is a pdb file in the same directory although i am never asked for it)

Having looked at some more functions, I really think that the de-compiler is quite messed up. Some of them are completely wrong