Repos in the same org not able to run `gh stack submit`

Last Friday, I was testing stacked PRs for our org, and I was able to submit two stacked PRs in `repo-a`. This week, I am able to submit stacked PRs in `repo-b` and `repo-c` within the same org, but not in `repo-a`. I am getting the error:

> $ gh stack submit
> Checking stack state...
> ⚠ Stacked PRs are not enabled for this repository
> ? Would you still like to create regular PRs?

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I tried the following API calls to diagnose:
`gh api -i 'repos/MyOrg/repo-b/stacks?per_page=1'` - returns `200`
`gh api -i 'repos/MyOrg/repo-a/stacks?per_page=1'` - returns `404`

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`gh`: `2.97.0`
`gh-stack`: `0.1.0`

Start by reproducing `gh stack submit` in `repo-a` and compare the `gh api` responses for `repo-a` and `repo-b`. Trace the repository stack-state check in the gh-stack entry point, then identify why the endpoint returns 404 and verify that submission behaves correctly for repositories in the same organization.

Written by the indexing model from the issue text.