Mosiac_undesire result

Hi everyone,

I have undesired result of mosiac. I was wondering I did sth wrong in processing step. I did as below:
1- Resample of two images ( same as B2 )
2- Multi-Mosiac of two resample image
I got one problem here: I could not select the mosiac method BLEND or OVERLAY (as shown in image)

After I run Multi-Mosiac (even I couldn’t select BLEND or OVERLAY), I got the undesired result ( shown in image) it seem there were two line where the two different images are overlay.
Could you share me your experience? I really want to know it is my mistake or sth wrong with program.

However, if I dont resample (use the L1C or L2A without resample), the mosiac optional method (BLENG or OVERLAY) is enabled (I havent check the result yet since I prefer 8bands to mosiac)