Acts_as_taggable_on - custom_contexts not working.

Hello,

For my rails application i have declared questions model as
acts_as_taggable_on. For this i am using dynamic context tagging. For
me Question.custom_contexts which is expected to give list of contexts
doesn't work and returns empty array, though there are custom
contexts.
But after using Questioin.tag_list_on(:applications) and then trying
to run Question.cutom_contexts return ["applications"] array.(and so
on for all other custom contexts.) What might be problem? Is this
some kind of caching plugins uses or a bug?

Sorry,
A correction - Question.tag_list_on(:applications) is wrong.. i use
Question.tag_counts_on(:application)