Using conditional includes (exists rules) from an included template does not work.

I have a common CI template that projects consume. It sets up basic build jobs, runner parameters, &c. Now I am trying to use conditional includes based on the presence of a file -- for instance, to add gradle caching to the build job if we detect the project uses gradle based on the presence of a gradle.properties file.

Example:

my-project/.gitlab-ci.yml

include:
  - project: ci-templates
    file:
      - common.yml

ci-templates/common.yml

...
include:
  # enable gradle caching if this is a gradle project
  - local: cache-gradle.yml
    rules:
      - exists:
        - gradle/wrapper/gradle-wrapper.properties

foo:
  script: ["echo foo works"]
  rules:
      - exists:
        - gradle/wrapper/gradle-wrapper.properties

in the above, cache-gradle.yml is never including, despite gradle/wrapper/gradle-wrapper.properties existing in the project.

What's super frustrating is that the foo job does run, and it shares the same rules! Why does the include exists rule behave differently than the job exists rule?

Is there a way we can conditionally include behaviuor using exists from our common template? I saw !75250 (closed) and thought @mwoolf 's idea of referencing a project to include could help but it appears stalled.