I raised this question with an examiner (EASA rather than FAA) very recently. I expressed the view that my FAA 'piggy-back' PPL was not current as I am not in-date with an FAA BFR. He told me that I did not require an FAA BFR as the FAA 'piggy-back' licence was rendered valid by my EASA PPL, BFR etc. being fully up to date.
Does anybody 'with stripes' have a clear view on this? Where can I verify this; Part 61.75(g) is not explicit, not to me at least?
(PS. I'm using the term BFR 'cos its easy and we all know what it means in both EASA-land and FAA-land).