When I right click on a chart to reload chart history. It comes back with "No data available" and the data set becomes corrupted. If I close and reopen Wealth Lab, the data is still missing after the attempted update.

This problem is the same with Yahoo and WealthSignals data.

Yahoo has been working fine in WL8 but is broken in the unsupported legacy version so yes, an attempt to reload will result in "No data available". There is no shortage of suggestions for alternative data providers in recent forum topics - or you might give Wealth-Lab 8 a try.

There is no "WealthSignals data" but you probably mean "WealthData historical data provider". It is working correctly for all of its supported symbols. Keep in mind that not all symbols are supported: WD FAQ: What Symbols Are Included?. Add S&P 500 to that list, the website isn't updated for this change. So if your symbol is not among supported symbols, its data cannot be returned by the Wealth-Data provider.