After updating from Alpha3 -> Alpha4, nodes being saved after uploading image.

I got a problem after updating 7.x-3.0-alpha3 to -> jquery_update 7.x-3.0-alpha4

If i edit a node and upload an image with plupload to an image_field, the node was saved automatically in stead of showing me the thumbnail in the node.

After downgrading to Alpha3, everything was normal again.

After upgrading again to Alpha4, the node was again saved automatically after uploading an image with plupload in the image_field.

Any idea what the problem could be?