Patch Request in Java Spring Boot nulls ManyToOne

I have this entity:

@Entitypublic class Rating {    @Id    @GeneratedValue(strategy = GenerationType.AUTO)    private Long id;    private Boolean isNa = false;    private String comment = "";    @Min(0)    @Max(5)    private Integer points;    @ManyToOne    @JoinColumn(name="audit_id", nullable=false)    private Audit audit;    @ManyToOne    @JoinColumn(name="question_id", nullable=false)    private Question question;    // ....}

when I perform a JsonPatch in a PatchMapping, the fields autdit and question are set to null, which in turn ensures that I cannot save the rating.

Here is my PatchMapping:

    @PatchMapping("/api/v1/ratings/{id}")    public ResponseEntity<Rating> updateRating(@PathVariable("id") long id, @RequestBody JsonMergePatch patch) throws ChangeSetPersister.NotFoundException, JsonPatchException, JsonProcessingException {        Rating entity = findRatingService.findRatingById(id).orElseThrow(ChangeSetPersister.NotFoundException::new);        JsonNode entityJsonNode = objectMapper.convertValue(entity, JsonNode.class);        JsonNode patchedEntityJsonNode = patch.apply(entityJsonNode);        Rating patchedEntity = objectMapper.treeToValue(patchedEntityJsonNode, Rating.class);        Rating updatedEntity = saveRatingService.saveRating(patchedEntity);        return ResponseEntity.ok(updatedEntity);    }

patchedEntity.audit is allways null

My Example Request Body:

[    {"op": "replace","value": "foo","path": "/comment"    }]

I have also tried slightly modified forms in the controller. But I am slightly stuck here and would appreciate any advice.

I've tried JsonPatch instead of JsonMergePatch