Issue Some users have trouble dragging an audio-video clip into the Timeline. When the clip is dragged in to the Timeline, only the video or audio portion of the clip appears. Very frustrating, but there's a simple fix. It's called Source Patching.
Make sure source audio and video (blue boxes) are patched in the Timeline before dragging or editing the clip to the Timeline.
Patching is indicated when the blue boxes are selected in the V1 and A1 tracks and are viewed as "V1" and "A1"
If selected, boxes indicate that audio and video are patched to specific "targeted" tracks, which are by default, V1 and A1.
The boxes should appear automatically after selecting the clip in the Project panel. If not, click either box that might be unselected.
You should now be able to drag the clip (or use the Insert or Overwrite buttons) to edit the clip into the Timeline properly.
Super clear and helpful explanation. Thanks so much. I just started teaching myself Premier 2 weeks ago to edit a music video, it went very well. HUGE learning curve haha. But starting project #2, I ran into this issue. And your video is the only one I found that hit it so directly and simply. Thank you!!