Opened the file in another app and said "all fine" without comparing the results

Any kind of task

Situation: Checking whether a spreadsheet works correctly in a different spreadsheet app.
What the AI did: It opened the file in the other app, saw every sheet display, and reported "all sheets OK." For the few cells whose results could change between apps, it looked only at how they appeared and never compared the values.
How to ask next time (the operator's example): "Instead of 'all OK,' first list the places where the result could change in a different app. Then show which of those you checked and which you didn't."
One question to ask: Where could a different app change the result, and was each of those places checked?
Check it yourself: For each cell on that list, increase the decimal places in both apps and read the full values side by side. A file that opens without errors can still compute different numbers.
AI used (month): Claude Code (2026-09)
Times this mistake was recorded: 5 times
Source: The operator's work records (the details were changed to a different task), and videos by Yuru Computer Science Radio (a Japanese YouTube channel)