Internal bug: b/260148546

Hello,
We are showing a dialog after Navigation. We recently migrated to the Navigator 2.0 api (pages passed by a router delegate), and our dialogs broke:

• When popping the dialog from Navigator.pop(context), it may get stuck.
  and require the app to restart. Suspending and resuming is not enough.
• The attached app is able to reproduce the problem by creating a tree of the form:
  [FutureBuilder] -> [Navigator] > [showDialog]

Seems reproducible under two conditions. (There may be more):

• A) Building the navigator pages under a FutureBuilder. This builds the
  Navigator multiple times with a "different" List that contains the same
  elements. Navigator checks "pages != oldPages" and the dialog gets
  removed.
  This isn't surprising if the dialog was considered part of the
  prior Paged route, but it is surprising that the overlay remains stuck.
• B) The route is replacing a previous page.

See the attached app here:

https://dartpad.dev/?id=fe55c717f2c144936493f0fb49802289