WorkBuddy Excel merge messed up my department schedule; anyone else experienced this?

Conclusion: I'm not daring to use the table merging feature anymore.

Background first. I posted previously about saving half my life using WorkBuddy for scheduling. That time was generating a schedule from scratch; with clear instructions, the results were indeed okay. So this time I wanted to take it further, summarizing last month's and this month's scheduling data—night shifts per person, rest days, compensatory leave balances—to draft a performance evaluation table.

Result: Crash and burn.

I put two months' Excel schedules into one folder and asked it to auto-merge. The first output had completely messed-up dates, the same person's night shifts appeared twice, and one person was missing. I thought it was a file format inconsistency issue, so I standardized the column headers across three tables to be identical and ran it again. Still wrong. The most infuriating part is that it doesn't throw errors; the page shows "Completed," and the result sits right there. If you don't check carefully, you won't notice anything.

Later, I scrolled past a Bilibili video discussing the 10 strongest AI tools of 2026, praising the auto-archiving feature to the heavens. I tried the prompt template from the video, and it improved slightly, but this month's night shift statistics still didn't add up.

I don't know if merged cells in Excel caused it to read incorrectly, or if I should convert all sub-tables to CSV before processing? Has anyone done similar data aggregation with WorkBuddy? Do merges always result in errors, or did I set something up wrong?