Hi Tümer
Greetings from Syncfusion support.
In the core platform ID is mandatory to render the EJ2 components. so, when you have repeated the form with same ID the component will not render again using duplicate ID property. that is the reason the component will not render the form repeater. We suggest you use unique ID to render each component when render the form to achieve your requirement.
Regards,
Sureshkumar P.