Double track showing ISSUE - Logic Pro X

This is normal behavior, when expanded a stereo track show both L/R channels, when shrunken it shows a single waveform. You haven't done anything except expand and open a stereo track. At least that's what it looks like from here.

My guess is somehow you created a stereo recording from your mono source.

This not about Logic but basic audio concepts. Mono vs Stereo.

WD

In fact, stereo can also be represented as a single wave, with the left side on top and the right side on the bottom. As soon as you zoom in (enlarge) vertically, at a certain point Logic displays the left and right sides as full waves, with again the left side on the top and the right side on the bottom. It's just a matter of graphics.

A single wave mono will be symmetrical, a single wave stereo will be asymmetrical. If it is a mono track, it will always show a single wave irrespective of the zoomed size.

It is normal. This is a Region pointing to a Stereo Audio file.

Do you remember what you did to get there?

WD