Is a failure to attach a document to a proof of claim sufficient to invalidate a claim?

^11. Such a failure is not even fatal to the proof of claim itself. The failure to attach documents may deprive the claim of presumptive validity but does not permit disallowance of the claim. See Heath v. Am. Express Travel Related Servs. Co. (In re Heath), 331 B.R. 424, 433 (9th Cir. BAP 2005) ("It is generally held that failure to attach writings to a proof of claim does not require a bankruptcy court to disallow a claim on that basis alone. Rather, the claim is not entitled to be considered as prima facie evidence of the claim's validity." (citation omitted)).