Some of it can, and we want to be exact about which parts. To write code, the agent sends prompts to the AI model provider you choose, and a prompt can include table and column names, schemas and sample values from your data. With your own model key, prompts go to that provider under your key and its terms. With a paid plan's included usage or usage credits (on Enterprise, metered usage), they pass through Emolysis's metering service on the way to the model provider; that service is designed not to store or log their content. A dashboard leaves your machine when you publish it, and only then.
Your platform credentials stay in your machine's credential store, and samples you pull are stored in the project on your machine. Deployed pipelines run on your platform, under your account.
The security page has the full list under "What leaves your machine", and the data handling docs go through each case. See also what the model provider sees and what Emolysis stores.