Hi @SM22! Welcome to the Community-- happy to have you here 
I understand you are adding Deal and Line Item data into Google Sheets via workflows, as described in this Knowledge Base article.
Could you clarify if you see this issue when adding new data for the first time, or is this happening when you try to update data? If the latter, the KB above describes that if multiple rows have matching values, only the first row containing the matching cell will be updated. If this is happening with net new data only, then please attach a screenshot of the workflow action and describe a specific example, so we can dig a bit deeper!
Maybe some of our experts have additional context. @karstenkoehler & @james-portant any ideas why only the first line item of a deal is syncing to Google Sheets? Is this expected?
Best,
Kennedy