I usually prescent at least a half an hour, typically closer to an hour or so. My feeding process usually goes...

Start prescent and 30 minutes later I thaw out the f/t for the boas, then once they are ready I start to feed.

I never thought to leave prey in the enclosure, just seemed like it would never work if she wont take one alive and wriggling. I have not handled her since her first week off feed, and nothing in the environment or husbandry has changed recently. I will try to feed in a dimmer light this weekend, with a longer prescent and see how it goes, and if it doesnt, I can leave a f/t overnight.

I thought about the fact that she just might be fasting from putting weight on so fast, but it seems a little delayed. She was on 4 mice a week, but it has been almost 2 months since I cut her back down to 2/week, so why fast now?