Its not in the level, its a spawnable actor. But yeah you will get some frame drops with the mirror, you shouldn’t be getting massive stuttering with a high end system though unless you really upped the screen percentage…Scene capture components are re-rendering the scene so they come at a hefty cost.
You aren’t on oculus are you? Heard there were perf issues with the oculus sdk in 4.17.
Edit Just saw that you mentioned oculus and 4.17 already…nvm my last sentance