Describe what you were doing when the bug occurred:
1. I was using the devtools to investigate some performance issues w/ an app I help maintain
2. I had just turned on the "Record why each component rendered while profiling" checkbox
3. I ran a profile while navigating on the underlying page

The react profiler tab in the devtools gave this error, I think as I clicked the record icon to stop recording the profile.

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DevTools version: 4.5.0-355970aa4

Call stack: at N (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:40:160881)
    at j (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:40:160015)
    at j (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:40:159939)
    at j (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:40:159939)
    at j (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:40:159939)
    at j (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:40:159939)
    at j (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:40:159939)
    at j (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:40:159939)
    at j (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:40:159939)
    at j (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:40:159939)

Component stack: in ec
    in div
    in div
    in div
    in So
    in Unknown
    in n
    in Unknown
    in div
    in div
    in rl
    in Ze
    in fn
    in Ga
    in _s
let fiber = renderer.findFiberByHostInstance(hostInstance);
    if (fiber != null) {
      if (findNearestUnfilteredAncestor) {
        while (fiber !== null && shouldFilterFiber(fiber)) {
          fiber = fiber.return;
        }
      }
      return getFiberID(getPrimaryFiber(((fiber: any): Fiber)));
    }
    return null;
  }
  const MOUNTING = 1;
  const MOUNTED = 2;
  const UNMOUNTED = 3;
   This function is copied from React and should be kept in sync:
   https:github.com/facebook/react/blob/master/packages/react-reconciler/src/ReactFiberTreeReflection.js
  function isFiberMountedImpl(fiber: Fiber): number {
    let node = fiber;
    if (!fiber.alternate) {
       I
       y
      if ((getFiberFlags(node) & Placement) !== NoFlags) {
        return MOUNTING;
      }
      while (node.return) {
        node = node.return;
        if ((getFiberFlags(node) & Placement) !== NoFlags) {
          return MOUNTING;
        }
      }