How to remove stuttering when stitching together videos?

I am creating extended AI-generated videos (creating a 10-second video with an AI tool and then using the end frame to extend the video further and then stitching them together with CapCut). I’m wondering why I have stutters in my video from exactly the point where the first part of the video ends (the first 10-second clip) and the next segment begins.

I see a line (in the attached picture, you can see it, too) in the timeline, and I was wondering if there is something I'm supposed to do with that.

I'd be grateful for any assistance with this. If it’s possible to fix it, it would be a joy. Thank you all! ❤️

I am creating extended AI-generated videos (creating a 10-second video with an AI tool and then using the end frame to extend the video further and then stitching them together with CapCut). I’m wondering why I have stutters in my video from exactly the point where the first part of the video ends (the first 10-second clip) and the next segment begins.

I see a line (in the attached picture, you can see it, too) in the timeline, and I was wondering if there is something I'm supposed to do with that.

I'd be grateful for any assistance with this. If it’s possible to fix it, it would be a joy. Thank you all! ❤️