If you're working with a popup containing a gallery list and a block inside it, and facing issues while fetching data, there are a few specific areas you might want to check:

1. Data Binding Between Parent and Block: Ensure that you're properly passing the required data from the parent screen to the block inside the popup. Use input parameters in the block to bind the data dynamically when the popup opens.

2. Block Events: If the block needs to send information back to the parent screen, use block events. Define an event in the block and handle it in the parent screen to update the gallery or fetch the correct data.

3. Filters in Aggregates: If the issue is related to displaying incorrect data (e.g., showing the same data for all items in the gallery), verify that the filters of your aggregate are dynamic and use the appropriate identifiers (e.g., the ID of the clicked card or gallery item). This was also highlighted in the article "[toggle popup from block in gallery<>https://www.outsystems.com/forums/discussion/59026/toggle-popup-from-block-in-gallery/]".

4. Popup Data Handling: When opening the popup, make sure you're refreshing the aggregate or data source that will feed the popup to ensure the most up-to-date results. This aligns with advice given in Error Popup/Modal after using Pagination.

5. Testing Data Flow in Debugging: Use the OutSystems debugger to monitor how data flows from the parent screen to the popup and block. Check whether the data is being correctly passed and used where it's needed.

If you're able to provide more details about the specific issue (e.g., is the data not showing, or is incorrect data being displayed?), I can help narrow down the problem further. Let me know!