Communication from Adobe:
We strongly recommend updating your current Premiere Pro installation to 13.1.3,
which provides over 300 important bug fixes, including a critical bug fix for AAF
Premiere Pro 13.1.3 fixes a critical issue with AAF exports from Premiere Pro where
some source media associated with XMP may be deleted after rendering. This issue only
occurs in versions 13.1, 13.1.1, and 13.1.2 of Premiere Pro.
Install the 13.1.3 update via your IT Administrator, through the Creative Cloud desktop
application or from Premiere Pro by choosing Help > Updates.
For more information about the 13.1.3 patch for Premiere Pro, visit our Help pages.