I have a formgroup which contains 2 mat-select and an input field. In the first group I select a value from the first mat-select and accordingly the second mat-select gets populated with data for that selected value from the first mat-select. Then I select a value form the second mat-select and then enter a value in the third control which is a simple input. Then I press a button to add another formgroup, now when I select a value from the first mat-select the value of the second mat-select in the previous grouparray disappears from view but when I check the form values, it is there. I dont understand what is triggering tis event. Can somebody please help me find the cause and resolve the issue.
<div formArrayName="rawmaterialwh">
<div [formGroupName]="i" *ngFor="let product of products.controls; let i=index">
<legend>{{i+1}}</legend>
<div class="form-group row">
<div fxLayout="row wrap" fxLayoutAlign="space-between center">
<mat-form-field>
<mat-select formControlName="supplier" class="form-control"
(selectionChange)="onSupplierValueChange($event)" placeholder="Supplier">
<mat-option disabled selected hidden>Supplier</mat-option>
<mat-option *ngFor="let supplier_mode of supplierOption"
[value]="supplier_mode.supplierid">{{supplier_mode.name}}</mat-option>
</mat-select>
</mat-form-field>
</div>
</div>
<div class="form-group row">
<div fxLayout="row wrap" fxLayoutAlign="space-between center">
<mat-form-field>
<mat-select formControlName="rawmaterialid" class="form-control" placeholder="Raw Material"
(selectionChange)="onProductValueChange($event)">
<mat-option disabled selected hidden>Product</mat-option>
<mat-option *ngFor="let product_mode of productOption"
[value]="product_mode.rawmaterialid">{{product_mode.rawmaterialname}}</mat-option>
</mat-select>
</mat-form-field>
<div fxFlex.gt-sm="49" fxFlex.gt-xs="49" fxFlex="100">
<mat-form-field class="full-wid mrgn-b-md">
<input matInput placeholder="Quantity" formControlName="qty" id="{{ 'qty' + i }}">
</mat-form-field>
</div>
<button *ngIf="!_isUpdating" class="mrgn-all-xs" class="mrgn-all-xs" mat-mini-fab color="warn"
(click)="deleteProduct(i)">
<mat-icon>delete</mat-icon>
</button>
</div>
</div>
</div>
</div>