I knew that Unreal's FBX importer can mess up unit conversion and produce models with local translations off by a factor. E.g. didn't convert m to cm, so model displays correctly but local translations are 100x too small.
But my mind has again been blown today: a user has a model that imported with local translations off by 1000, and component space scale off by 100.
...
I maintain my position that Epic should ship a working importer before they are allowed to make new features.