Error: Call to a member function getIncludes() on null

Problem/Motivation

Using this module with ContentaCMS and Contenta_vue_nuxt consumer, on a fresh install, request :
api/recipes?include=image,image.thumbnail&fields[images]=thumbnail

Raise:

Error: Call to a member function getIncludes() on null in Drupal\jsonapi\Normalizer\EntityNormalizer->normalize() (line 107 of modules/contrib/jsonapi/src/Normalizer/EntityNormalizer.php).

Proposed resolution

Add a test for $normalized_field before calling getIncludes().

Remaining tasks

Reviews needed

User interface changes

None

API changes

None

Data model changes

None