First you need to remember a BP is a wild animal so striking and bites can and will happen sooner or later.

If there is a change all of the sudden it could be due stress due to husbandry issues!

How long have you had her for?

How big is your enclosure?

Is your enclosure in a low traffic area?

What are your temps (cool & warm side)?

What is your humidity?

What type of thermometer/hygrometer do you use (dial,stick,or digital)?

What kind of hides do you provide (log, homemade, cubbyholes etc) and how many do you have?

Are your hides tight (all side touching your BP's body) and identical?

How often do you handle your BP?

Is your BP in shed?