I've connected through FRA at least a half a dozen times recently and have had the scanner buzz when walking through the security checkpoint. This was after passing through security at various European airports 2-3 hours prior, with never a buzz. Note that I make sure there's nothing remotely metallic on my person, including shoes/jewelry/coins etc.

This is certainly not a big deal, but I am wondering if anyone else has had a similar experience at FRA.