Dragging a stereo clip onto two mono tracks creates two mono clips
Occasionally, you'll have a stereo audio clip where one side might be a boom mic, and the other might be a wireless lapel (lav) mic.
A nice feature would be the ability to drag that clip over two mono tracks, and have Audition automatically split the clip into two separate mono clips, which can then be edited and mixed independently.
And if it IS a true stereo file, you can still split when dragging to Mono audio tracks by holding CTRL+ALT. This only forces separation when the destination tracks are mono, though.
When dragging in a 2-channel (non-stereo, which you're describing) file, you can hold down the ALT(Windows) or OPTION(Mac) key to separate the channels to separate clips on separate tracks. You can also twirl open multichannel audio files and select one or more arbitrary channels to drag in, and the same keys will separate those as well.