I researched several plugins that create this twitter widget in the Facebook style. This is certainly one of the best, especially about the client side requests.
Twitter has a limit of 150 requests accepted per hour, and after that limit, it no longer returns the results.
However, I identified a bug in followers loading. After print the followers list, with each thumbnails, the list is reloaded indefinitely. Probably some problem with the loop that makes this task.
So, in a single page view, the limit of 150 requests to Twitter is exceeded for that user.
I know that the plugin has not been maintained, but it would be interesting to fix this little problem, to make it useful again.