They pretty much mean the same thing. The difference is a matter of what is being emphasized. The clause that begins with ALTHOUGH is the subordinate clause, so the main emphasis would be on the clause that does not begin with ALTHOUGH.

They definitely aren’t clear because of the world ‘careful’. There’s no obvious connection between being careful and bringing a phone. Are you saying that she’s making an effort to remember to bring her phone, but not being successful? Is it known that going out is dangerous and having a phone is important for increasing her security? Because of that lack of connection, ‘although’ doesn’t make sense either. You could say: Although she knows it’s safer to carry a phone, she still forgets sometimes. Although she tries to remember to carry her phone, she still forgets sometimes. If you switch the order, ‘although’ isn’t the best. She never carries her phone even though she knows it’s safer to. She sometimes forgets to carry her phone, even though she tries to remember to.

Yes, the second sentence is correct: "She is careful although she still forgets her phone when she goes out." Differences: 1. Sentence Structure: - First Sentence: "Although she is careful, she still forgets her phone when she goes out." - This structure emphasizes her carefulness first and then introduces the contrasting idea of forgetting her phone. - Second Sentence: "She is careful although she still forgets her phone when she goes out." - Here, the main statement is about her being careful, and the contrast is introduced afterward. 2. Emphasis: - First Sentence: The emphasis is on the idea that being careful doesn't prevent her from forgetting her phone. The focus is more on the contrast. - Second Sentence: The emphasis is on her carefulness, indicating that even though she is careful, it doesn’t guarantee that she will remember her phone. It suggests that her carefulness exists despite the forgetfulness. Both sentences communicate a similar idea but with slightly different emphases and flows.