unescaped characters in regexp

[alpha-er]

When regexp param has unescaped characters, e.g.

- name: javascript-file
    type: s3
    source:
      bucket: releases
      regexp: my.website.com/scripts/my-javascript-(.*).js
      access_key_id: ((aws_id))
      secret_access_key: ((aws_key))
      region_name: ((aws_region))

It fails the resource check with:

resource script '/opt/resource/check []' failed: exit status 1

stderr:
�[31merror listing files: SerializationError: failed to decode REST XML response
caused by: XML syntax error on line 2: illegal character code U+0010
�[0m

But when the chars are escaped in regexp param, i.e.

regexp: my\.website\.com/scripts/my-javascript-(.*)\.js

It fails the put step with:

error running command: AccessDenied: Access Denied
	status code: 403

Anybody else came across with this problem and if there's a workaround?