Why were notifications sent after I added or deleted rows?

Check Sheet remembers which cells have already matched your check by their position in the spreadsheet.

If you insert rows in the middle of data that Check Sheet is monitoring, delete rows, or move rows around, the position of existing values can change. When that happens, Check Sheet may see those values in new cell positions and send notifications again.

This is similar to what can happen when a sheet is sorted directly. For the full explanation, read Why were notifications sent after I sorted my sheet?.

How to avoid this

Where possible, add new rows at the bottom of your sheet instead of inserting them into the middle of existing data.

Avoid deleting rows from the middle of the range monitored by your check, because this can shift the rows beneath them into new positions.

If you want to change the order of your data, add new records at the bottom and use a Google Sheets filter view to display the data in the order you need. Filter views let you sort and filter what you see without physically moving the rows in the sheet.

What to do instead of deleting rows

If you need to keep a record but do not want it to trigger a check any more, consider changing its status or moving it outside the range monitored by your check.

If you do need to delete rows, duplicate notifications should stop once the sheet structure stays stable again.