Couplers for Stainless Steel Bars

[bridgebuster]

I'm finishing a bridge project that will be using stainless steel rebar, and will require over 100,000 couplers. Recently, our client said they became aware of problems with forged couplers (as opposed to machined couplers) for SS bars, no other info.

I was wondering if anyone had any insights. For the time being, we're going to specify machined couplers only.