[destus]

либо

<input formControlName="login" matInput [ngModel]="user.login" />

либо так

<input formControlName="login" matInput />

this.userService.getUser(+this.currId)
		.subscribe((data: IUserCard) => {
			const user = new UserCard(data);
            this.emplForm.get('login').setValue(user.login);
            this.emplForm.get('full_name').setValue(user.full_name);
		});