Hey Skye, thanks for flagging this! I've recently asked the team to consider CSV imports as a JSON source so data could be stored at a cell level just like other sources i.e. webhooks, where you click and extract the data.
The default, since that's not currently the case for CSVs it's why mapping the data from a source column to static standalone columns would try to add the data from the JSON objects. Since you only have 1 row with a webhook but the rest are empty under it, the formula assumed those were empty and thus replaced the values accordingly.
I'll share this as an example with the team and see if we can get this going. Your current workaround is definitely the best way to handle... merging the imported column from CSV and the value from the webhook into a final column.
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