Audit field history and activity logs

Audit field history and activity logs for account 004928 (Harris Manufacturing) for the past 90 days. Produce a concise list of who changed Opportunity Stage, Amount, and Close Date, include timestamps and the before-and-after values, and flag any activity that looks like a bulk update so I can bring it to legal by Thursday.

Before I run the audit for the client, make the findings easy to act on — surface the biggest anomalies up front, show which user accounts account for most changes, summarize bulk edits versus single updates, and call out any changes that align with contract amendments so a reviewer can decide if escalation is needed.

Harris Manufacturing called saying pipeline totals shifted since yesterday and their account exec, Malik, is upset. I pulled the activity logs and see many Stage changes after midnight across the account team. I don't know whether this was a bulk data cleanup, an integration job, or accidental edits. What's the most likely diagnosis and the fastest way to confirm the cause so I can tell Malik and leadership?

We repeatedly wake to unexpected field changes that erode trust with account teams and trigger expensive audits. What one operational habit should we adopt to prevent silent overnight edits, who must own it, and what minimal monitoring or alert would catch most problematic changes before they damage relationships?