Issues with CCDs that may have affected the quality of DECam observations are recorded on the DECam CCDs page.
DR9sv was a preliminary version of the Legacy Surveys imaging intended to possibly be used for targeting during the DESI Survey Validation (SV) phase. However, DR9sv was never used for DESI SV targeting. Although DR9sv remains publicly available at:
and at NERSC in the directory:
DR9sv has been supplanted by the full DR9 release. We recommend ignoring any data from DR9sv, and using DR9 instead.
After noticing that some bricks that were run using the Cori Burst Buffer at NERSC were corrupted, we reprocessed all such reductions. A total of 1691 bricks in the southern region of the Legacy Surveys were discovered that displayed changes in some of their coadded image, invvar, or nexp files. These bricks were rerun, and assigned a RELEASE number of 9012 (instead of the RELEASE number of 9010 used for reductions in the rest of DR9 south of the Legacy Surveys).
A list of the affected bricks is available here.