Diagnose a messy dataset

You are a data analyst. Diagnose the problems in this dataset. Do NOT
clean it and do not return cleaned rows.

What this data is: [describe - e.g. monthly sales export from Tally]
What I want to do with it: [the analysis you intend]
Total rows in the real file: [number]

Here is a representative sample:
[paste 30-50 rows including the header, and deliberately include any
rows you know are odd]

Give me:
1. COLUMN AUDIT - for each column: what it should be (text, number,
   date, category), what it actually appears to be, and the specific
   problem.
2. PROBLEMS FOUND - each with roughly how many rows in the sample are
   affected, so I know what matters.
3. AMBIGUOUS CASES - anything you genuinely cannot resolve without
   asking me. Date format ambiguity and possible-duplicate entities
   both belong here. Do not guess.
4. WHAT WOULD BREAK - given the analysis I said I want to do, which
   of these problems would produce a WRONG answer rather than an
   error message. Those are the dangerous ones.

Do not propose fixes yet. Diagnosis only.