I think that shows that you have a pretty good understanding of these tenses!These sentences are all made up. I didn't take them from any book so there's no additional context I can provide. Here is how I understand the sentences.
In 1) the action is in progress i.e. she is behaving strange now. Sentence 2) is a general statement about her behaviour. The last sentence suggest that the action happened in the past.
What do you think?