trying to fix a strange instantiation / reference bug

src/pages/show-text/show-text.html

@@ -51,23 +51,23 @@
                 <ion-title>{{ 'EXERCISE_FEEDBACK' | translate }}</ion-title>
                 <ion-item>
                     <ion-label>{{ 'EXERCISE_FEEDBACK_GENERAL' | translate }}</ion-label>
-                    <ion-textarea [(ngModel)]="exerciseProvider.exercise.feedback.general" name="feedbackGeneral"></ion-textarea>
-                    <!--placeholder="{{ 'EXERCISE_FEEDBACK_GENERAL_DEFAULT' | translate }}"-->
+                    <ion-textarea [(ngModel)]="exerciseProvider.exercise.feedback.general"
+                                  name="feedbackGeneral"></ion-textarea>
                 </ion-item>
                 <ion-item>
                     <ion-label>{{ 'EXERCISE_FEEDBACK_CORRECT' | translate }}</ion-label>
-                    <ion-textarea [(ngModel)]="exerciseProvider.exercise.feedback.correct" name="feedbackCorrect"
-                                  placeholder="{{ 'EXERCISE_FEEDBACK_CORRECT_DEFAULT' | translate }}"></ion-textarea>
+                    <ion-textarea [(ngModel)]="exerciseProvider.exercise.feedback.correct"
+                                  name="feedbackCorrect"></ion-textarea>
                 </ion-item>
                 <ion-item>
                     <ion-label>{{ 'EXERCISE_FEEDBACK_PARTIALLY_CORRECT' | translate }}</ion-label>
-                    <ion-textarea [(ngModel)]="exerciseProvider.exercise.feedback.partiallyCorrect" name="feedbackPartiallyCorrect"
-                                  placeholder="{{ 'EXERCISE_FEEDBACK_PARTIALLY_CORRECT_DEFAULT' | translate }}"></ion-textarea>
+                    <ion-textarea [(ngModel)]="exerciseProvider.exercise.feedback.partiallyCorrect"
+                                  name="feedbackPartiallyCorrect"></ion-textarea>
                 </ion-item>
                 <ion-item>
                     <ion-label>{{ 'EXERCISE_FEEDBACK_INCORRECT' | translate }}</ion-label>
-                    <ion-textarea [(ngModel)]="exerciseProvider.exercise.feedback.incorrect" name="feedbackIncorrect"
-                                  placeholder="{{ 'EXERCISE_FEEDBACK_INCORRECT_DEFAULT' | translate }}"></ion-textarea>
+                    <ion-textarea [(ngModel)]="exerciseProvider.exercise.feedback.incorrect"
+                                  name="feedbackIncorrect"></ion-textarea>
                 </ion-item>
             </ion-list>
         </ion-list>

src/providers/exercise/exercise.ts

@@ -6,7 +6,6 @@ import {QueryMC} from "../../models/queryMC";
 import {AnnisResponse} from "../../models/annisResponse";
 import {TranslateService} from "@ngx-translate/core";
 import {Feedback} from "../../models/feedback";
-import {NodeMC} from "../../models/nodeMC";
 
 /*
   Generated class for the ExerciseProvider provider.
@@ -22,7 +21,7 @@ export class ExerciseProvider {
             phenomenon: Phenomenon.pos,
             value: PartOfSpeech.conjunction
         }),
-        feedback: new Feedback()
+        feedback: new Feedback({general: "", incorrect: "", partiallyCorrect: "", correct: ""})
     });
     public annisResponse: AnnisResponse;
     public MCapiExerciseUrlString: string;