Repro: https://codesandbox.io/s/fast-water-4i4jb

Notice the flash. I'd expect `suspended` to be `true` during the high pri render.
workInProgress.effectTag |= Placement;
  }
  const props = workInProgress.pendingProps;
  let context;
  if (!disableLegacyContext) {
    const unmaskedContext = getUnmaskedContext(
      workInProgress,
      Component,
      false,
    );
    context = getMaskedContext(workInProgress, unmaskedContext);
  }
  prepareToReadContext(workInProgress, renderExpirationTime);
  let value;
  if (__DEV__) {
    if (
      Component.prototype &&
      typeof Component.prototype.render === 'function'
    ) {
      const componentName = getComponentName(Component) || 'Unknown';
      if (!didWarnAboutBadClass[componentName]) {
        console.error(
          "The <%s /> component appears to have a render method, but doesn't extend React.Component. " +
            'This is likely to cause errors. Change %s to extend React.Component instead.',
          componentName,
          componentName,
        );
        didWarnAboutBadClass[componentName] = true;
      }