**Core Insight**
The L402 production issue arises from the failure to return the cryptographic preimage to the client when a Lightning payment is internally settled by the same custodian, undermining the client’s proof of payment and potentially leading to verification failures.
**Key Analysis**
The heart of the issue is that the preimage serves as an essential cryptographic proof of payment
The L402 production issue arises from the failure to return the cryptographic preimage to the client when a Lightning payment is internally settled by the same custodian, undermining the client’s proof of payment and potentially leading to verification failures.
**Key Analysis**
The heart of the issue is that the preimage serves as an essential cryptographic proof of payment