Visual glitch with my primitive shapes

I tried unsuccesfully to find something about this on google and in here, so sorry if this has already been asked before.

In my project, i use rectangle to generate a terrain when tge game start. The rectangle has a x value of 100, y value of 1 and z value of 2. When i run the app on my phone, there is some visual glitch appearing between rectangles used to create my terrain. It looks like a strip with a slightly differente color that goes all the way through the x axis between both object. I really dont know what may cause this issue. I already verified and my objects arent instantiated one on top of the other.

Here is 2 picture showing those strips.

http://imgur.com/a/fycuA And http://imgur.com/a9yIfBQ

Both picture have been taken at same place and pretty much same time, you can see the strip is somehow flashing and changing colors.