Scenario:
One or more list fields appear twice on the forms associated to a list (new, edit and view). There are no duplication in the list columns. The list is using a custom content type.
For example the Answer field shows twice on the New FAQ form:
Things to look for:
Check that the field/column is not declared twice in the list settings page.
Cause:
I have seen this happening in 2 cases:
1. when changing and re-deploying the underlying content type
2. when migrating lists from one site to the other (using PowerShell in my case)
Fix:
Browse to the list settings page (on the List Tools - List ribbon click on the List Settings icon)
