I have been keeping and breeding BP for 11 years now, I have used aspen, sanichip, cypress mulch, and now coco coir chips (since October 2016) and have done so with hatchling and adult without any issue.

Can something happen? Well nothing is ever risk free I guess however keep in mind that BP are designed to digest fur, bones, and nails so a little substrate will be no issue.

In their natural environment there are probably all kind of debris sticking to the prey when ingested, and they are still around.