Code Snippet Issue Identification

PitchBook ingests funding round records from multiple data partners and merges them into one company funding history before analysts see them. The function below is producing funding histories with duplicate rounds and rounds in the wrong order. Identify the potential issues in this snippet of code.

def merge_funding_rounds(records):
    cleaned = []

    for r in records:
        r["round_date"]  # string like "2023-05-01" or "05/01/2023" depending on source
        amount_usd = r["amount"]

        is_duplicate = False
        for c in cleaned:
            if c["amount"] == amount_usd and c["round_date"] == r["round_date"]:
                is_duplicate = True

        if not is_duplicate:
            cleaned.append(r)

    for r in records:
        if r.get("amount") is None:
            records.remove(r)

    cleaned.sort(key=lambda r: r["round_date"])

    return cleaned

Walk through what could go wrong here and why.