Thanks for that reply. What you suggested worked. I think I didn't actually try that.
I know I said I tried "UID_MIN" in sssd.conf but that's only because I
forgot what the actual parameter was. I had looked at the man page for sssd.conf and saw
'min_id' like you suggested. However, it says that that parameter applies to all
domains (not just local) and it has a default value of '1'. Because of that I
assumed that it was not the issue. However, maybe the LOCAL domain is a special case and
has a different (as you said 1000) default value for 'min_id'.