BUG #13875: Error explaining query

The following bug has been logged on the website:

Bug reference:      13875
Logged by:          Travis Smith
Email address:      travis.smith@iriworldwide.com
PostgreSQL version: 9.5.0
Operating system:   Linux lnx0409.ch3.prod.i.com 2.6.32-358.el6.x86_64
Description:

=# explain select count(1) from (SELECT DISTINCT
"IRI_IT_M_2782_7472_O"."ATTR_VALUE", "IRI_IT_M_2782_7472_O"."SORT_ORDER",
"IT_DIM_IRI_7472"."M_2796_KEY", "IT_DIM_IRI_7472"."M_2782_KEY" FROM
"IT_DIM_IRI_7472", "IRI_IT_M_2782_7472_O" WHERE
("IT_DIM_IRI_7472"."S_848_KEY" = 4527492) AND
("IT_DIM_IRI_7472"."M_2782_KEY" = "IRI_IT_M_2782_7472_O"."AVP_KEY") ORDER BY
"IT_DIM_IRI_7472"."M_2796_KEY" ASC, "IRI_IT_M_2782_7472_O"."SORT_ORDER" ASC,
"IT_DIM_IRI_7472"."M_2782_KEY" ASC  ) t;

ERROR:  variable not found in subplan target list