After importing a Static Mesh, if you alter any build settings and apply changes, on the next opening of the Project you will not be able to reimport the asset changed. You will have to retarget the location of the FBX and reinput all import settings.
This is a regression of behavior in 4.8.2.
Also test via Github: ue4 4.9 github branch, commit 8f66c95f1d88ed4560258e35851a9974a48c6581
RESULTS: You are asked for the asset's location. If you look in Property Matrix, the asset is no longer listed as an FBXAsset.
EXPECTED: On Reimport Asset, it should happen automatically since we have already established import settings for the mesh.
Head over to the existingAnswerHub thread and let us know what's up.