Depending on where in time you paste it (grin). Paste it out of sync a hair and it makes a huge difference..
Even then, phasing can make it seem to jump toward center occasionally.

The L/R exact copies of tracks appearing centered, reminds me of how reversing a files 'polarity' and playing both versions at the same time can make absolute silence!
Use Audacity to flip a file and it will sound pretty much the same.
Then open that file and the original in RB on two separate tracks..if you get the volumes to match they will cancel each other (if they both are centered). You can actually use the volume or panning to control the amount of cancellation .
Funny how sound works.

I do not work here, but the benefits are still awesome
Make your sound your own!