Trends values: the current curve and the older one are mixed

Hello,

I have currently the same issue, we are developing a machine with WinCC Unified HMI,

We plot curves (function xy trend control) from JSON files, we can navigate between files with .sh files and each time we plot a new curve, the current curve and the older one are mixed (see attached screenshot).

This problem don't appears in PC Simulation, 

Did you resolved this problem since ?

Thanks

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Split from How can i clear a trends values? (Data source logging tag).