It appears the NOT_DEBLENDED mask is not getting set properly. See DM-16151 for details.
Diagnose potential issue with setting of NOT_DEBLENDED mask
Fred Moolekamp, just assigned this older ticket to you - can you see if this is still a problem for either meas_deblender, Scarlet, or both, and if so, fix it?
Sure, I can check on both. With DM-27929 there is now a test that checks the NOT_DEBLENDED flag in meas_extensions_scarlet matches the expected NOT_DEBLENDED flag. So I can add a similar test to meas_deblender to make sure that this doesn't happen again. If it's ok I'd prefer to get to this after DM-27929 and DM-28980, since those tickets refactor meas_extensions_scarlet and meas_deblender respectively.
Yup, no rush at all - this has been lingering for ages, but we figured it was one we could actually do properly without too much difficulty instead of just giving up or punting.