$form_build_id validation fails when 2 or more forms exist

My Setup:

1. A content type with an image file upload field
2. Panel override for the node edit form of said content type
3. Pane 1 - General node form
4. Pane 2 - Embedded View: Draggable views

Problem:

• Clicking "Upload" or "Remove" on the image file upload field on the node edit page (overridden by panels) throws the following error:
  An unrecoverable error occurred. The uploaded file likely exceeded the maximum file size...

Expected Behaviour:

• Clicking "Upload" or "Remove" on the image file upload field on the node edit page should either upload the image, or remove it.

Discovery:

• Looks like there are two form_build_id on the page. One for the node edit form, and one for the embedded draggable view form.
• The error occurs when the file field form_build_id validation grabs the form_build_id from the embedded draggable view, and not the node edit form
• Looking at the rendered node edit page source HTML I see a tag for the general node edit form (wrapping around the node edit form and the embedded draggable views form), but no tag around the embedded draggable view.
• Disabling the embedded draggable view alleviates the problem, but re-enabling the draggable view sees the issue return (obviously)

Sanity Checks:

• No mod_sec installed
• php.ini post_max_size with plenty of room
• php.ini upload_max_filesize with plenty of room
• /tmp (php.ini and drupal) permissions all correct and working
• Running on a Linode, so no issues with hidden shared hosting quirks
• Filesystem & file fields on other content types work without issue (and even on this content type, but only if not overridden with two form_build_id on the node edit page.

Since the error is coming from file.module after grabbing and attempting to validate the wrong form_build_id, this seemed to me to be the most logical place to post the issue.