Since our Manual Heatmap screenshots are designed to remain the same so that you can revise your old designs and compare them with newer ones, you may not see them updated if you change any design elements in your site.
Solution: Our recommendation would be to duplicate your Heatmap after a design change, to ensure that you're able to measure user interactions with a the updated layout/design:
This way, you will have snapshots of your past designs as well.
Continuous Heatmaps behave differently
If you're using Continuous Heatmaps, you will not have the option to create a duplicate Heatmap. This is because Continuous Heatmaps are generated on-demand, rather than being stored as snapshots. Learn more about Continuous Heatmaps.