[Bug]: Ethereum USDT estimate accepts 4 USDT but funded deposit fails below minimum #1764

What happened?

3.1 release blocker — manual sanity case RS-BRIDGE. A fresh Ethereum → Arbitrum USDT estimate accepted 4.00 USDT, showing 1.28 USDT deduction / 2.72 USDT estimated credit. After the exact 4 USDT source transfer succeeded, Android showed Needs attention, with below_minimum / xchain_amount_too_small. The bridge did not complete.

Linked investigation: synonymdev/bitkit-ios#1197 — iOS 2 and 2.5 USDT attempts failed identically and both were fully refunded. This Android attempt is now refunded: the full 4 USDT returned to the same MetaMask Ethereum address.

Expected behavior

Reject amounts that cannot meet execution constraints before presenting funding instructions. An accepted estimate should be consistent with the standing-deposit execution requirements, with clear handling of any remaining execution risk.

Steps to Reproduce

1. On the existing mainnet wallet, open USDT → Receive → Network → Ethereum.
2. Enter 4 USDT and obtain a fresh estimate: 1.28 USDT deduction, 2.72 USDT credit.
3. Continue to the deposit address and manually send exactly 4 USDT on Ethereum.
4. Open Cross-Network Deposits and the new deposit.
5. Observe Needs attention; locally inspect the support diagnostics for below_minimum / xchain_amount_too_small.

These are completed reproduction steps, not a request to spend more mainnet funds.

Logs / Screenshots / Recordings

• Source transaction: Ethereum Success, exactly 4.000000 USDT, 2026-11-03 14:45:35 Europe/Warsaw, block 26334659; 4,000,000 token base units.
• Ethereum USDT contract: 0xdAC17F958D2ee523a2206206994597C13D831ec7.
• Deposit address: 0x9E6C59d51801C540d2018f49Fd72a7D1b7E3447a.
• Deposit reference: xit_c13b81db-a38c-4a4a-bc95-97351db0a048.
• Source gas: 0.00014313356015919 ETH, separate from the 4 USDT deposit.
• Refund completed; Samsung shows Refunded. Support form inspected locally and closed unsent.

Asset: USDT
Bridge: Orchestra
Source network: Ethereum
Recipient network: Arbitrum One
Deposit reference: xit_c13b81db-a38c-4a4a-bc95-97351db0a048
Status: Needs attention (below_minimum)
Source transaction: 0x775f3b32b0b285c9253076a4f07036238fa0858eed328ef01d7b1c8a17781436
Status code: xchain_amount_too_small

Bitkit Version

3.1.0 (196), release head d13769269cf17737100e092d66b2bc9236bc8eb8.

Device / OS

Samsung Galaxy S22 (SM-S901B), Android 16. Existing mainnet wallet preserved.

Reproducibility

1/1 funded Android attempt at 4 USDT. Together with the linked iOS report: 3/3 funded attempts failed (2, 2.5 and 4 USDT). Other amounts and routes are untested.

Additional context

• Blocks release sign-off while this route remains enabled. Resolve with a verified fix and successful funded route/minimum checks, or disable the affected route and verify both clients prevent new deposits through it.
• An estimated net credit above 2 USDT did not resolve the rejection. No safe minimum is established; stop larger trial deposits pending execution evidence.
• Cross-platform symptom suggests the shared service/provider path, but exact root cause and whether this is a 3.1 regression remain unproven. Estimates are indicative; the reusable standing address does not lock execution pricing.
• Prior unfunded Android preflight: 1 USDT rejected with a $2 minimum; 2 USDT estimate accepted (~0.68 deduction / ~1.32 credit).
• Release PRs: chore: bump version 3.1.0 #1755 and chore: bump version 3.1.0 bitkit-ios#1193.
• Distinct from closed Android [Bug]: Solana USDT quote minimum shows decimal-format error and persists after amount edits #1520 / iOS chore: bump version 2.3.0 #964 (quote error formatting) and Android bug: usdt receive doesn't warn that only arbitrum one deposits arrive #1557 (receive-network warning).

Android refund verified

Samsung shows Refunded for xit_c13b81db-a38c-4a4a-bc95-97351db0a048. The full 4 USDT refund succeeded on Ethereum at 2026-11-03 15:01:23 Europe/Warsaw, block 26334738, returning exactly 4.000000 USDT to 0x6a405Cf34fBF1d5160445f890AdF64E9A80646Fb. All three deposits' principal is recovered (8.5 USDT total); original source gas remains spent. Refund recovery passed; the failed bridge case and 3.1 blocker remain open.