I'm trying to set up multiple matchers on a smart variable. When I do so, I receive the following error...

PGError: ERROR: value too long for type character varying(255) : INSERT INTO "audits" ("action", "associated_id", "associated_name", "associated_type", "auditable_id", "auditable_name", "auditable_type", "audited_changes", "comment", "created_at", "remote_address", "user_id", "user_type", "username", "version") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15) RETURNING "id"

The full trace is...
ActiveRecord::StatementInvalid
PGError: ERROR: value too long for type character varying(255) : INSERT INTO "audits" ("action", "associated_id", "associated_name", "associated_type", "auditable_id", "auditable_name", "auditable_type", "audited_changes", "comment", "created_at", "remote_address", "user_id", "user_type", "username", "version") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15) RETURNING "id"
app/controllers/puppetclasses_controller.rb:32:in `update'
app/models/concerns/foreman/thread_session.rb:33:in `clear_thread'
lib/middleware/catch_json_parse_errors.rb:9:in `call'

The input was as follows:
The value in the "Order" field was
os,fqdn
and the value in the "Match" field was
os=stupid,fqdn=dummy

From the way I read the documentation for implementing multiple matchers, this should have worked. Am I perhaps misreading the documentation?