0x – Problem with 0x Protocol Goerli API

I'm trying to test the 0x quote API, ran into an issue with the Goerli endpoint.

I sent a quote request to mainnet, to sell WETH and buy USDC:
https://api.0x.org/swap/v1/quote?buyToken=USDC&sellToken=WETH&sellAmount=100000000000000000

There is no issue, I received the correct response:

{"chainId":1,"price":"1323.97485","guaranteedPrice":"1310.7351","estimatedPriceImpact":"0","to":"0xdef1c0ded9bec7f1a1670819833240f027b25eff","data":"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","value":"0","gas":"125195","estimatedGas":"125195","gasPrice":"18500000000","protocolFee":"0","minimumProtocolFee":"0","buyTokenAddress":"0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48","sellTokenAddress":"0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2","buyAmount":"132397485","sellAmount":"100000000000000000","sources":[{"name":"0x","proportion":"0"},{"name":"Uniswap","proportion":"0"},{"name":"Uniswap_V2","proportion":"0"},{"name":"Curve","proportion":"0"},{"name":"Balancer","proportion":"0"},{"name":"Balancer_V2","proportion":"0"},{"name":"Bancor","proportion":"0"},{"name":"BancorV3","proportion":"0"},{"name":"mStable","proportion":"0"},{"name":"SushiSwap","proportion":"0"},{"name":"Shell","proportion":"0"},{"name":"DODO","proportion":"0"},{"name":"DODO_V2","proportion":"0"},{"name":"CryptoCom","proportion":"0"},{"name":"Lido","proportion":"0"},{"name":"MakerPsm","proportion":"0"},{"name":"KyberDMM","proportion":"0"},{"name":"Component","proportion":"0"},{"name":"Saddle","proportion":"0"},{"name":"Uniswap_V3","proportion":"1"},{"name":"Curve_V2","proportion":"0"},{"name":"ShibaSwap","proportion":"0"},{"name":"Synapse","proportion":"0"},{"name":"Synthetix","proportion":"0"},{"name":"Aave_V2","proportion":"0"},{"name":"Compound","proportion":"0"}],"orders":[{"type":0,"source":"Uniswap_V3","makerToken":"0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48","takerToken":"0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2","makerAmount":"132397485","takerAmount":"100000000000000000","fillData":{"router":"0xe592427a0aece92de3edee1f18e0157c05861564","tokenAddressPath":["0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2","0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48"],"uniswapPath":"0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc20001f4a0b86991c6218b36c1d19d4a2e9eb0ce3606eb48","gasUsed":65195},"fill":{"input":"100000000000000000","output":"132397485","adjustedOutput":"129967849","gas":99195}}],"allowanceTarget":"0xdef1c0ded9bec7f1a1670819833240f027b25eff","decodedUniqueId":"7ec526fe6c-1673274722","sellTokenToEthRate":"1","buyTokenToEthRate":"1323.97485","expectedSlippage":"-0.001112727338236046"}

I then sent the exact same request to the Goerli endpoint:
https://goerli.api.0x.org/swap/v1/quote?buyToken=USDC&sellToken=WETH&sellAmount=100000000000000000

It returned me the following error message:

{'code': 100, 'reason': 'Validation Failed', 'validationErrors': [{'field': 'buyToken', 'code': 1000, 'reason': 'buyToken and sellToken must be different'}, {'field': 'sellToken', 'code': 1000, 'reason': 'buyToken and sellToken must be different'}]}

Any idea what caused the issue here? Thanks for your time!