Found another issue with the double-quoted return_url and adding relationship fields to a form that even results in a hard error adding members to a group:
Index: www/admin/groups/elements-by-rel-type.tcl
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RCS file: /home/cvsroot/acs-subsite/www/admin/groups/elements-by-rel-type.tcl,v
retrieving revision 1.3
diff -r1.3 elements-by-rel-type.tcl
71c71
< set relations_add_url [export_vars -url -base "../relations/add" {group_id rel_type {return_url $return_url_enc}}]
---
set relations_add_url [export_vars -url -base "../relations/add" {group_id rel_type return_url}]
Index: www/admin/relations/add.tcl
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RCS file: /home/cvsroot/acs-subsite/www/admin/relations/add.tcl,v
retrieving revision 1.2
diff -r1.2 add.tcl
48a49
150c151
< attribute::add_form_elements -form_id add_relation -start_with relationship -object_type $rel_type
---
# attribute::add_form_elements -form_id add_relation -start_with relationship -object_type $rel_type