Crash report: `Error: invalid BigNumber string (argument="value", value="erc721", code=INVALID_ARGUMENT, version=bignumber/5.6.0)`

URL

https://app.uniswap.org/#/swap?chain=mainnet

swap state

{
  "INPUT": {
    "currencyId": "ETH"
  },
  "OUTPUT": {
    "currencyId": null
  },
  "independentField": "INPUT",
  "typedValue": "",
  "recipient": null
}

Error

Error: invalid BigNumber string (argument="value", value="erc721", code=INVALID_ARGUMENT, version=bignumber/5.6.0)

Stacktrace

Error: invalid BigNumber string (argument="value", value="erc721", code=INVALID_ARGUMENT, version=bignumber/5.6.0)
    at e.value (https://app.uniswap.org/static/js/3.dbad261b.chunk.js:2:83146)
    at e.value (https://app.uniswap.org/static/js/3.dbad261b.chunk.js:2:83290)
    at e.value (https://app.uniswap.org/static/js/3.dbad261b.chunk.js:2:83369)
    at Function.value (https://app.uniswap.org/static/js/3.dbad261b.chunk.js:2:172649)
    at Zn (https://app.uniswap.org/static/js/main.e5723063.chunk.js:1:360171)
    at Xn (https://app.uniswap.org/static/js/main.e5723063.chunk.js:1:359001)
    at https://app.uniswap.org/static/js/main.e5723063.chunk.js:1:361246
    at ti (https://app.uniswap.org/static/js/main.e5723063.chunk.js:1:361469)
    at oa (https://app.uniswap.org/static/js/3.dbad261b.chunk.js:2:1913815)
    at za (https://app.uniswap.org/static/js/3.dbad261b.chunk.js:2:1923382)

Device data

{
  "ua": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.64 Safari/537.36",
  "browser": {
    "name": "Chrome",
    "version": "101.0.4951.64",
    "major": "101"
  },
  "engine": {
    "name": "Blink",
    "version": "101.0.4951.64"
  },
  "os": {
    "name": "Mac OS",
    "version": "10.15.7"
  },
  "device": {},
  "cpu": {}
}

Reproduce the crash at https://app.uniswap.org/#/swap?chain=mainnet using the reported swap state, then trace the minified calls in static/js/main.e5723063.chunk.js and static/js/3.dbad261b.chunk.js back to source. Done means the same swap state no longer throws the invalid BigNumber error and the relevant regression is covered by a test.