WHERE condition lost from conditional unique index

I am attempting to apply an Unique Index in Postgresql with mixed results.
I am generating the index via a Ruby on Rails migration. The up statement
looks like:

execute("create unique index formatted_address_unit_number_and_status
on properties (formatted_address, unit_number)
where status = 'published';")

On my local development the index works as intended. If I take a look at
the properties table by running \d properties, the migration correctly
added index like so:

"formatted_address_unit_number_and_status" UNIQUE,
btree (formatted_address, unit_number) WHERE status::text = 'published'::text

However, when my Jenkins CI server runs the migration, I only see the
following in the propertiestable:

"formatted_address_unit_number_and_status" UNIQUE,
btree (formatted_address, unit_number)

Why would the migration work on my development but not on Jenkins? Am I
applying the unique index correctly to begin with?

--
Jake Fagan

Ruby Engineer
jakeofagan(at)gmail(dot)com
503.449.3464