Remove correct grade

src/main/java/nl/tudelft/submit/service/GradeService.java

@@ -766,15 +766,11 @@ public class GradeService {
 	 * @param submissionId The id of the submission
 	 */
 	public void removeHighestGrade(Long submissionId) {
-		submissionCache.getOrThrow(submissionId).getGrades().stream()
-				.max(Comparator.comparingInt(GradeSummaryDTO::getScore))
-				.map(g -> feedbackRepository.findAllByGradeId(g.getId()))
-				.orElse(Collections.emptyList())
-				.forEach(f -> {
+		Long removed = gradeApi.removeHighestGrade(submissionId).block();
+		feedbackRepository.findAllByGradeId(removed).forEach(f -> {
 			f.setGradeId(null);
 			feedbackRepository.save(f);
 		});
-		gradeApi.removeHighestGrade(submissionId).block();
 	}
 
 	/**