>As the sun sets, Ash and his friends talk to Nurse Joy, somewhat relived that Teddiursa evolved, allowing it to be able to find food without having to steal from humans, as well as not being able to charm. Ash and his friends head off to Olivine City. Meanwhile, Team Rocket has stopped, making popcorn, upset at losing the money to the farmer. Ursaring shows up and initially scares them, but doesn’t appear hostile and walks up to them. Its charm no longer works, but Team Rocket decides to befriend it, dancing. Ursaring dances with them, although a quick evil stare it gives Team Rocket make it clear that neither it nor their popcorn will be staying around for long...
--From Bulbapedia on the episode
Clearly, the ending is kind of unclear, and open to interpretation.
To make a comprehensive study of Charm:
>The user gazes at the target rather charmingly, making it less wary. This harshly lowers its Attack stat.
Again, the two statements that have been made bold are imperative to solving this:
>Its charm no longer works,
>a quick evil stare
making it quite clear that
No, Charm does not work.
It is merely Ursaring who is back to its old tricks, but since it now is bigger and more intimidatory, it doesn't need to use Charm anymore.