Mosaic with error on overlapping area

Hello! I need some help, I hope somebody can help me please, I’m don’t know which is the problem. I have two or more tiles of an area, some tiles is overlap when I try to make a mosaic with snap the result is that the area of overlap is the unique with correct values the other have values like 255, I don’t know which is my mistake. A image of the result.

Thank you very much.!

Can you tell a bit more, otherwise it is difficult to find an explanation for this.
Please let us know how you have configured the binning and which output format you use.

In the image you have proved the black area is 255 and the orange something around 128?
You can investigate the exact values by using the Pixel Info View. Also the histogram might be interesting.

Hello! Thank you for the answer.
I used the tiles of Sentinel-3 A and B level 2 WRR (after trying with the WFRR with the same result). I need to reproject before making the mosaic, I don’t remember it is necessary, but it’s work; I share an image of the result with reprojecting before the mosaic.