Colin S. pulled up the ellipticity residual plots (like those Lauren shared above) for w_18 and w_14, and the residuals are noticeably larger for w_18. Not sure if that is a concern.

Also, I'm curious about those figures – it says "cat forced scarlet" at the bottom. R. Lupton recently explained that once sources have been deblended by scarlet, their PSFs are not preserved, and they should thus not be used for ellipticity/shape assessment. To ensure non-deblended sources, I think instead of deblend_nChild==0, one has to use deblend_isPrimary and deblend_isIsolated. Can you guys confirm the correct source selection to use?

Hopefully before anyone goes searching in w_14, what I saw was that e1 residuals increased sometime after v21 (https://lsst.ncsa.illinois.edu/~emorgan2/v21_0_0_rc1_qaplots/HSC-R/tract-9615/plot-t9615-HSC-R-e1Resids-psfMagHist.png). It sounds like that's not the main issue here, but might come up again in the characterization report once the column issue is fixed.

Jeff, indeed, the label in the plot is telling you that these data come from the forced_src catalog and that the deblender in play in this processing was scarlet. As for the selection of objects, I am basically using detect_isPrimary but without the detect_isTractInner condition. This gives me the non-scarlet-model entry for isolated objects, but I am not selecting only isolated objects, so indeed many of the objects in these plots will have been subject to any PSF-destruction from the deblending process. In this sense, I totally agree that these should not be considered an official "metric" for PSF assessment (and, if anything, should be expected to show larger discrepancies). I do sub-select on the calib_psf_used flag, so you are only seeing stars that were deemed suitable for PSF modeling in the SFM stage, so this is a fairly pristine stellar sample...but now that we're looking at coadd depths, many will suffer from blending not seen at the visit-level (and, as has been much discussed, this does lead to deblending "issues" that now land these objects classified as galaxies [sic] on the coadds as evidenced by the red points in the plot). Since the "official" KPM-type defined metrics are computed elsewhere, this plot does not attempt to mimic it in any way (and all we have here are the src - psfModel (at position of src) residuals, the numbers here do not reflect the TEx metrics which refer to the correlations of these residuals on various angular ranges. So, I guess all my plots are demonstrating is whether this general distribution (mean and spread) is not changing run to run. Since it is entirely possible for the general distribution of the numbers going in to the TEx measurements could look similar in a simple scatter plot, but in reality have entirely different correlation patterns on the sky, the TEx values could indeed vary significantly. The best clue my plots can provide here is the visual provided by the "sky" and quiver plots. E.g. you could blink these to see if any pattern differences jump out (but I suspect that the metric may be more sensitive than the eye in this case):
https://lsst.ncsa.illinois.edu/~emorgan2/w_2021_14_qaplots/HSC-R/tract-9615/plot-t9615-HSC-R-e1Resids-sky-stars.png
vs.
https://lsst.ncsa.illinois.edu/~emorgan2/w_2021_18_qaplots/HSC-R/tract-9615/plot-t9615-HSC-R-e1Resids-sky-stars.png

or

https://lsst.ncsa.illinois.edu/~emorgan2/w_2021_14_qaplots/HSC-R/tract-9615/plot-t9615-HSC-R-ellipResids-quiver.png
vs.
https://lsst.ncsa.illinois.edu/~emorgan2/w_2021_18_qaplots/HSC-R/tract-9615/plot-t9615-HSC-R-ellipResids-quiver.png

We've found (and fixed) the bug causing the huge differences in ellipticity residuals, but it appears like there are still some subtle differences for reasons probably not linked to `faro` at all. So can we consider this ticket Done?

I think we sufficiently explored this, and I'm happy to call the ticket Done. Thanks!