After my Drupal 8.51 upgrade, I keep getting this error.
Uncaught PHP Exception Drupal\Component\Plugin\Exception\PluginNotFoundException: "The "ComplexData" plugin does not exist."
I have Googled it for two days and haven't found any information about what this is or how to fix it. I get the error while using Panels/Page Manager. I did upgrade both modules to the 4/14 release but that didn't help. Any ideas?