i had the same problem a few months back, my solution to this was checking for duplicate vertex, check if a face on the inside of the mesh is preventing the merge, and recalculate normals, that or your vertex isnt aligned to 0 properly.
most of the time i fixed it by recalculating normals with Shift N
hope it helps
Thanks to @mobin for prompting me regarding my cage, I did some further research and found out the proper way to do a cage.
My steps to resolve artifactings:
Duplicate lowpoly model, and name as Cage
Select all faces of Cage, alt s, to scale up the faces in normal directions
Toggle on mirror selection mode
Compare Cage to High Poly model, and push out all ...