Why do vive builds perform worse than editor and Oculus?

We’re seeing strange performance issues with our Vive builds. Our levels perform at a solid frame rate on Oculus-in Editor and in build. On Vive, we can run at framerate in editor in a legacy 4.9 preview 4 build, but haven’t been able to reproduce that in other engine versions. Our builds, however, lose as much as 30 fps from PIE. We have been forced to use older steamvr revisions in order to have acceptable in-editor performance. Is this a known issue?