Pull request across forks shows 0 of 0 changed or added relevant lines in 0 files are covered

I am using the Coveralls Github Action in my repository https://github.com/thephantomthief/babelfish_extensions.

There is a PR across branches on my repo, and the coveralls comment on that PR shows the correct relevant lines added: https://github.com/thephantomthief/babelfish_extensions/pull/18

However, if the PR is across forks, then the comment shows "0 of 0 changed or added relevant lines in 0 files are covered": https://github.com/thephantomthief/babelfish_extensions/pull/19. When I follow the build link to the coveralls web UI, in the source changed, it correctly shows the number of lines added/removed in each source file but when I open the source file, there are no source code lines highlighted that have been added. Seems strange.

I have read through the https://docs.coveralls.io/ and have followed the recommend CI configuration mentioned here: https://docs.coveralls.io/build-types#recommended-ci-configurations where the push builds are happening on the default branch and the pull_request builds are happening on all PRs targeted towards the default branch.

Another difference I noticed is that in the PR raised from and to the same repo, the comment is made by "github-actions bot" but on the PR raised across forks, it is made by "Coveralls".

Any help on how to get the comment on PRs raised across forks, to mention the correct number of lines added/changed would be greatly appreciated!

Compare the Coveralls comments and build links for PRs 18 and 19, then review the repository's GitHub Actions configuration against the recommended pull_request and push setup in the linked Coveralls documentation. Trace how forked pull requests are reported in the action and Coveralls UI; done means the fork PR comment reports the correct changed or added covered lines.