One of the very first b.p. I purchased started doing this after I'd had her a couple of months. She'd been on live prey when I purchased her at the age of 3 mos., but switched to f/t with no issue. After several feedings however, she started striking/coiling, and then moving away without feeding. After a couple of frustrating months during which time I'd offer her food every 7 - 10 days with the same result, I caved and offered her live. She nailed and ate before the rat pup had barely touched feet to floor and since that time has absolutely refused to eat anything but live.
I will never understand why she ate f/t so well initially, or why she suddenly decided she wasn't going to do it anymore, but for now, she's eating live. I will try f/t again at some point, but for now, apparently she's letting me know that the only thing she wants is live. (sigh)
Have you tried pre-killing and placing in when twitching still? I have no feeding issues with pre-killed when offered this way. Both my BPs will not eat FT but will eat pre-killed. Is a bit more traumatic for me to feed this way but it works and my BPs are safe.