Also, adding in.... don't feel like this is your fault! The info the prior owner left you with was flawed. So at some point in the 8 months you were 'babysitting' the snake could have been wanting for another couple of meals.
However...Even the healthiest ball pythons will sometimes decide to fast for a few months without warning. So the occasional food strike and weight loss is not unheard of. This may have been something to trigger the previous owner to say the snake was hibernating.