There are multiple heroes that share the same tag within a subtree.

[k3v1n-uncle]

════════ Exception caught by scheduler library ═════════════════════════════════════════════════════
The following assertion was thrown during a scheduler callback:
There are multiple heroes that share the same tag within a subtree.

Within each subtree for which heroes are to be animated (i.e. a PageRoute subtree), each Hero must have a unique non-null tag.
In this case, multiple heroes had the following tag:

Here is the subtree for one of the offending heroes: Hero
tag:
state: _HeroState#bda4c
When the exception was thrown, this was the stack:
#0 Hero._allHeroesFor.inviteHero. (package:flutter/src/widgets/heroes.dart:268:11)
#1 Hero._allHeroesFor.inviteHero (package:flutter/src/widgets/heroes.dart:279:8)
#2 Hero._allHeroesFor.visitor (package:flutter/src/widgets/heroes.dart:298:21)
#3 SingleChildRenderObjectElement.visitChildren (package:flutter/src/widgets/framework.dart:6105:14)
#4 Hero._allHeroesFor.visitor (package:flutter/src/widgets/heroes.dart:311:15)
...
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