TPP DOCX Upload Validation + Metadata Loss

What this skill debugs

This skill covers a paired issue class in the Third-Party Paper (TPP) request flow:

1. SpotDraft rejects a .docx with a generic Invalid DOCX file error even though the document opens in Microsoft Word.
2. After that failure, when the user replaces the file and retries, the TPP form loses all previously entered metadata.

These often appear together and should be investigated as two separate bugs:

• Backend validation strictness on non-standard DOCX XML structure
• Frontend state loss when the file entry is replaced after an upload error

When to use / when not to use

Use when: