* Was unable to create an issue on the Monero repo (I reckon due to the recent spam attacks there).
We ran into an overflow bug with `check_tx_key` `confirmations` on a `--regtest` setup.

Tested with `v0.16.0.3` and `v0.17.2.0` `--regtest` node with `--fixed-difficulty 1`
`check_tx_key` returns `u64::MAX` for `-1` (I reckon the tx is just not in mempool yet...?):
```
Apr 13 15:15:19.608 DEBUG swap{id=ca956c0e-c12b-4b7f-93d2-dc74f4814e90}: monero_rpc::rpc::wallet: check_tx_key RPC response: {
  "id": "1",
  "jsonrpc": "2.0",
  "result": {
    "confirmations": 18446744073709551614,
    "in_pool": false,
    "received": 1000000000000
  }
}
```

Consecutive calls seem to build on top of that error:
```
Apr 13 15:15:19.644 DEBUG monero_rpc::rpc::wallet: check_tx_key RPC response: {
  "id": "1",
  "jsonrpc": "2.0",
  "result": {
    "confirmations": 18446744073709551613,
    "in_pool": false,
    "received": 1000000000000
  }
}
```

Project where our tests ran into this issue:
https://github.com/comit-network/xmr-btc-swap

If you need more information please ping me directly via GitHub handle after creating a ticket: https://github.com/da-kami

Unfortunately don't have the time to look into a fix in the Monero codebase myself atm :)