WaterMaskImage with an unwanted new image frame

Up to Terrain Correction, there is no border for the image which is good. But after the texture analysis, a black border with a thickness of 10 m in average is created though!

As a result, after performing the water bandmath, this new frame (white dots on the figure) around my mask still exists with the same value of water bodies!

Another problem is that those water bodies on the boundary of image has no separate boundary in the sense that if I select only the new boundary created, for instance in ArcGIS, those water bodies on the boundary are also selected.

This is like they are one union feature! I only have this problem for those water bodies on the image boundary.
How to avoid creating a new frame for the image after water masking!
Any suggestion plz!