Editor and player crash after reparenting a RectTransform

I'm seeing a reproducible crash when reparenting a RectTransform. I think it might be similar to this crash:
https://issuetracker.unity3d.com/is...er-when-game-object-is-given-different-parent

What I'm doing is as follows:

1. Level select scene loads.
2. Reparent a UI hierarchy from a DontDestroyOnLoad Canvas to the canvas in the level select scene.
3. Level select scene fades in by animating a CanvasGroup alpha - the CanvasGroup is a parent of the hierarchy from (2).
4. When the player taps on a level in the level select screen, the CanvasGroup fades out.
5. When the fade out is complete, the UI hierarchy from (2) is reparented to the DontDestroyOnLoad Canvas.
6. A new scene is loaded asynchronously.

Right before I do the reparenting, I set the root GameObject of the UI hierarchy to active/inactive, and that's where it crashes.

This has only started happening after I upgraded my project from 5.4.3f1 to 5.6.0.f3. It's a big problem because we're planning on releasing our game soon, and this is a major roadblock right now.

I've reported a case here. Has anyone seen this crash, or does anyone have a workaround? I haven't been able to find a consistent workaround yet.

I haven't been able to recreate it in a blank test project yet, because I'm not exactly sure what the conditions are that are causing it, and I don't have the time right now to carefully pull the game apart to work it out.

Thanks,
Sam