Thank you very much @DavidPike for your quick response!
My mosaic had black edges that I needed to get rid of, so instead of using "Geometry" as a computation method while building footprints, I used "Radiometry" and added a negative shrink distance which helped remove the white line.
The only problem that I'm facing right now is the difference in colours between different sections of my mosaic, the North and South are much brighter than the middle part. I had solved this problem in the past by building statistics and colour balancing the mosaic using "Enhance ► Colour Balance (Balance Method = Dodging, Surface Type = First Order). When I Colour Balanced my mosaic after applying the shrink distance, the results weren't good at all, the tiles boundaries became apparent (see attached image)
Any idea on how to solve this?
Thanks again!