https://www.drupal.org/project/drupal/issues/3554919
Stop discovering theme preprocess twice for theme engine discovered templates [#3554919] |...
Dec 24, 2025 - Problem/Motivation Themes always get an extra chance at the end of \Drupal\Core\Theme\Registry::processExtension() to add preprocess to everything, and then...
stopdiscoveringthemepreprocesstwice