bug(zk): MerkleWitnessUnavailable when sending to a new address with no prior transactions

[lklimek]

Description

When attempting to send shielded funds to a new address that has no prior transactions, the operation fails with a ShieldedMerkleWitnessUnavailable error. The local note commitment tree cannot construct a valid Merkle witness because the frontier data is missing the expected root.

Error

ShieldedMerkleWitnessUnavailable {
    detail: "invalid frontier data: witness failed: Tree does not contain a root at address Address { level: Level(0), index: 233 }"
}

Steps to Reproduce

1. Have a wallet with shielded balance
2. Attempt to send shielded funds to a new address that has never received any transactions
3. The operation fails with the above error

Expected Behavior

Sending shielded funds to any valid address should succeed regardless of whether the recipient address has prior transaction history. The Merkle witness construction should not depend on the recipient's transaction state.

Environment

• Observed on Dash Evo Tool (testnet)
• Using SPV mode

_{🤖 Co-authored by Claudius the Magnificent AI Agent}

[lklimek]

it doesn't work even for address that has some funds (address from different wallet), sync / resync doesn't help.

Destination address: tdash1zp49ttwghu4u0yr2e6wj4d2z3x660vxpz4nvlrvdjlrxu4v68tv4f5pjgvea7ecj48cplrszq6200

ShieldedMerkleWitnessUnavailable { detail: "invalid frontier data: witness failed: Unable to compute root; missing values for nodes [Address { level: Level(4), index: 14 }]" }

[QuantumExplorer]

Most likely the real issue is a discriminant issue on the address.