Problem:
Gauldur's Amulet is supposed to be gold. The original mesh has vertex colors on the centerpiece to make it gold. When USSEP fixed clipping issues in #918 it changed the model to "ancientnordamulet" assuming it was identical (sans clipping issues) but "ancientnordamulet" does not have vertex colors and appears to be bone or ivory in color.
Note that the ground/inventory mesh has always appeared bone/ivory in color. This is because "brokenamuletassembledgo.nif" is an unfinished placeholder and vanilla uses "ancientnordamuletgo.nif" instead. Given that the other meshes are gold, it's reasonable to assume the intent was to make the placeholder mesh into a gold version of "ancientnordamuletgo.nif".
Proposed Solution:
I have created new "brokenamuletassembled" meshes (including a ground/inventory mesh) by copying "ancientnordamulet" meshes and adding the appropriate vertex colors.
The USSEP plugin needs to be modified to revert the existing changes to the Gauldur's Amulet model path and point its ground/inventory mesh to the newly fixed "brokenamuletassembledgo.nif".
Zip file with proposed changes attached.

Attached Files:
Unofficial Skyrim Special Edition Patch - Gauldurs Amulet Fix.zip