1 project can use the runner when the other cant

We are currently experiencing an issue with the pipeline in our project project1 · GitLab. The pipeline is stuck with the following error message: “This job is stuck because of one of the following problems. There are no active runners online, no runners for the protected branch, or no runners that match all of the job’s tags: internal.”

Despite this error, we can confirm that the runner associated with the tag “internal” is active and live. It appears that the pipeline is unable to utilize the available runner for reasons we cannot determine.

What’s particularly perplexing is that the same tag and runner configuration work flawlessly in other projects, such as the one at Projext · GitLab.
both are under the same subgroup
However, there are instances where even in these successful projects, we encounter the same error intermittently.