Worked on the plotly/plotly.js repository to address a critical issue affecting data visualization accuracy in high-volume dashboard applications. Focused on JavaScript front end development, the work involved fixing stale error bars in Scattergl plots when toggling trace visibility, particularly in scenarios with mixed error bar settings. The solution required updating error handling logic to ensure error bars update or clear correctly as traces are shown or hidden. Automated tests were added to validate the new behavior and prevent regressions. All changes were carefully localized to the plotting path, maintaining rendering performance while reinforcing the reliability of data visualizations.