Date invalid when inserting with mat-datepicker

Question

When inserting the date by typing in the input in the format dd / mm / yyyy the field becomes invalid making my form invalid not allowing to save the record.

But if I use datePicker and insert the date the field becomes valid.

Even though I use datePicker and after inserting the value in the input with datePicker copying the value and pasting in the input is getting invalid ...

The date is only valid if I use datePicker ... I can not insert date writing in dd / mm / yyyy format.

The datePicker is inserting date in the input format with dd / mm / yyyy, I typed the date in the input in the format dd / mm / yyyy but the date is considered invalid.

The problem only occurs when I type the date in the input, the date is only valid if I insert the date in the input through the datePicker.

myform.ts:

this.formBuilder.group({
            date: [''],
        });
   ........................

myform.html:

<mat-form-field fxFlex>
    <input matInput [matDatepicker]="DatePicker" formControlName="date" name="date" placeholder="Date">
    <mat-datepicker-toggle matSuffix [for]="DatePicker"></mat-datepicker-toggle>
    <mat-datepicker touchUi="true" #DatePicker></mat-datepicker>
</mat-form-field>

Since my form is very large, I've just put what is causing me a problem when saving the record.