Yii 2 PJAX call on form submission

Hi there,
I’m using Yii2’s PJAX to submit a form. On the first submission, everything works perfectly—the controller receives the request and renders a partial view as expected. However, on the second submission (without a page reload), the form submits in the normal way (full page reload) instead of using PJAX.
Has anyone encountered this issue before or know what might cause PJAX to stop working after the first submission?