As noted by mreno in a Slack message:
the current Codex UI for http://folio-testing.aws.indexdata.com is sending "ext.available" for these check boxes. The Codex CQL schema extension (https://github.com/folio-org/raml/blob/master/schemas/codex/codex_instance_cqlschema-ext.json) defines "ext.selected". Sending "ext.available" causes a failure in mod-codex-ekb (mod-codex-ekb probably shouldn't report errors for unknown "ext" fields). Also, if both available online and not available are checked, this is sent: "ext.available=("true" or "false")". The extension set defines "true", "false" and "all" as expected values. In the case both are checked "all" should be sent. If this is problematic, then we need to rethink how mod-codex-ekb handles this CQL field. I didn't look at the latest UI code, so this could all be fixed.