Don't use placeholders functionality of rendering for basic string token replacement
- drupal 8 render arrays on same page same output
- drupal 8 field formatter caching
Wasn’t really the render array part but the placeholder part and i still don’t understand how it caused the age results to be replaced with the grades results.
But i was mis-using placeholder API anyway.
All i really wanted was the t() function without the translation parts.
- drupal 8 list of render elements