The resampling parameter for the reprojection seems to be ignored.
The results look all the same.
In addition, if the data type of a band is integer then always nearest neighbour is applied. This was probably introduced to prevent interpolation of flags and index bands, but how it is implemented is not the right way.
This imagesshows the results when using OLCI with a pixel-based geo-coding.
GPF tests shall be created to ensure the correct results.
This has been reported in the forum:
After further looking into this issue, it turns out that the problem is related to pixel-based geo-coding.
If the product which is reprojected uses a tie-point-based geo-coding the interpolation works, if the geo-coding is CRS based it work's too.
This image shows an OLCI scene which was reprojected using a tie-point-based geo-coding
This image shows the results (bicubic, nearest) of the reprojection of an S2 MSI scene (CRS).