Very easy to reproduce:
- Add 2 tracks - can be MIDI, Instrument Track, or Audio. Make sure both tracks are the same type.
- Draw or record a region on both tracks
- Show Lanes on the second track (So you see Lane 1, Lane 2)
- Drag & drop the region from track 1 onto the “Lane 2” of the second track.
- The dropped region will not drop on “Lane 2” but will be bumped up to “Lane 1”
I’m not 100% sure if this is by design - if it is, it’s an productivity-killing design.
Here is a video that illustrates this: