# Known Issues

For issues relevant to DECaLS imaging, consult the DR5 issues page.

## Repeat Sources Due to Check-pointing

The legacypipe code applied a series of check-points in case of failures during processing. Unfortunately, when the code resumed after a check-point failure, it sometimes produced a duplicate of the same source. These duplicates can be identified because they have identical coordinates and fluxes but a different OBJID. An example repeated source is here:

https://www.legacysurvey.org/viewer-dev?ra=215.8471&dec=0.0805&zoom=16&layer=decals-dr5&sources-dr5&bricks

This source has the following attributes in catalog-level DR5 data:

Attribute

Source 1

Source 2

RA

215.84766

215.84766

DEC

0.080533681

0.080533681

BRICKID

331231

331231

OBJID

4938

4941

TYPE

DEV

DEV

FLUX_G

5.86150

5.86150

FLUX_R

22.1008

22.1008

FLUX_Z

47.8499

47.8499

FLUX_W1

28.0480

28.0480

(i.e. fluxes and coordinates are identical but OBJID is different).

In DR6, we estimate that there are many thousands of duplicates spread across 264 bricks. The full list of DR6 bricks that contain duplicates, and the number of duplicates in each brick, is available here.

## One brick was processed with a different pipeline version

Brick 1228p810 was processed with a different stack of codes, as detailed at the bottom of the description page.