Bunnylady
Herd Master
I'd never heard or read of Flemish or NZs hiding otter though.
Obviously, somebody did an outcross somewhere in the past, possibly to a Silver Marten, though Rex and Satin come in Otter, as do several non-commercial-type breeds. It's amazing what can lurk unseen for generations. I had REW's pop up in my pedigreed Harlequins at one point; there must have been a NZW several generations back (probably why that line had such good type!) I've also had Fuzzy Lops turn up in Holland Lop litters; unless you get the right two rabbits together, you may never know just what is in your gene pool.