Ember 3.27.0 - Receiving "[BUG] seen set should be available" Error

[kiwi-josh]

This usage works fine in ember 3.24:

{{#if-flag MY_CONDITIONAL}}
  <p>Hello World</p>
{{/if-flag}}

However is causing this error when after upgrading to ember 3.27:

Template Compiler Error (TemplateCompiler) in my-app/components/account-payments-page/prompt/template.hbs

Assertion Failed: [BUG] seen set should be available

[kiwi-josh]

I accidentally closed this, so will reopen for visibility.

I worked around the issue by using macroCondition instead, but it isn't as succinct syntax, nor aggressive at removing deadcode:

i.e. changed from:

{{#if-flag MY_CONDITIONAL}}

to:

{{#if (macroCondition (macroGetOwnConfig "MY_CONDITIONAL"))}}

[oscarni]

Thanks for pointing out a workaround.

Seeing the same on 3.28, also with the latest master which looks to have ember 4.x work done on it.