variable faq_omit_vocabulary not resetting

furthermore, If I set omit in faq advanced category settings for one vocabulary (by ex: vid = 7), the faq_omit_vocabulary variable is set like this:

Array
(
    [7] => 7
    [8] => 0
)

with the result that either the nodes depending on the vid 8 aren't shown.

setting manually the variable to:

Array
(
    [7] => 7
)

it works.

please correct this bug.