I have just come across this issue when updating from 18.4.26.12 to 19.7.15.12.
Like the OP in https://www.nevron.com/Forum/12739/When-is-it-adviceable-to-call-NevronChart100ocumentCalculate-and-RecalcLayout I started getting numerous problems where no chart data was drawn in the newer version.

I also eventually tracked down that removing the Calculate resulted in the chart reappearing again.
I wasted considerable time tracking this down. It would have been good if some mention of this was made in release notes (or did I miss it?).

This is clearly a bug here that needs fixing.

Hi Kevin,
It is hard to tell why the chart did not function properly, but we're considering to remove the Calculate method now because it actually takes two passes to completely recalculate the control in order to take care of things like dynamic axis y range etc, axis synchronization and others. In addition, the new version adds optimizations for removing redundant range calculations some of which may be causing this behavior on your end. The recommended way to recalculate the control is through the RecalcLayout method now as it will completely reevaluate all display time properties. If you send us an example that replicates the problem we can be more specific about the cause...

Best Regards,
Nevron Support Team