There are several possibilities. She might be a bit shy or hesitant to reply to your text directly. Watching your story could be her way of showing some level of interest without fully engaging in a conversation. Or perhaps she was in a situation where she couldn't text back immediately, like being in a meeting or with family, but had a moment to quickly look at your story. Another reason could be that she doesn't really want to have a deep text conversation but is casually interested in your updates as shown by watching your story.
Perhaps he's a bit shy or hesitant to respond to your text directly. By watching your story, he can keep a bit of distance while still being involved. It might also be that he was in a hurry when he saw your text and only had time to quickly view your story.
Maybe she was just too busy at that time. There could be a lot of things on her plate, like work, study or taking care of family. So she might not have had the time to check your story.
You could send her a friendly message asking if she saw it. For instance, 'Hey, I noticed you didn't watch my story. Just wanted to make sure you're okay.'
Well, it might be that they're trying to keep their distance while still being a bit nosy. They didn't wish you a happy birthday because they don't want to give you the wrong idea that they want to be back in your life in a big way. But watching your story shows that they're still interested in what's going on with you on some level.
I asked my beautiful leader if she liked me and she said she didn't. I began to doubt her true thoughts, but her answer made me feel at ease. I decided to let go of this crush and continue to focus on my work. Although it may be difficult, I believe that as long as I focus on my career, I will eventually find someone more suitable for me.