Intermittent "Required runner group 'x' not found" errors

[MaheswariS03]

Describe the bug
We've encountered intermittent "Required runner group 'x' not found" errors during runner assignment in our GitHub Actions workflows.
Runner assignment process observed:

• GitHub actions workflow is triggered
• GitHub scheduler verified runner group exists and sent a request to AWS through GH App webhook
• AWS initialized an ec2 runner and registered in the runner group
• Our ec2 runner took ~2:30min to complete initialization and start processing the job
• Meanwhile, intermittently a job failed in <2min with "Required runner group 'x' not found" error
• In the same workflow matrix, runners got assigned to some jobs successfully and failed for some jobs with the error

We didn't find anything notable in the runner runner/syslogs/user-data logs. Runner remained idle (waiting to pick up a job) until it was terminated, based on worker logs.
we are looking for a direction to investigate..

Job definition:
jobs:
build:
runs-on:
group: x
labels: [ self-hosted, u22-ephem ]
strategy:
fail-fast: false
matrix:
build_matrix: ${{ fromJson(inputs.build_matrix) }}
steps:

Runner group policy:

• allows access to my repository
• Access allowed for all workflows
• Other jobs in the same workflow are able to pick up runners for job compilation

To Reproduce

• Occurs intermittently

Runner Version and Platform

• Runner version - 2.331.0
• OS Platform - Ubuntu 22.04 & 24.04

What's not working?

user-data & Runner's Diagnostic Logs

[aestinar]

we are also experiencing this issue, any resolution or updates? thanks

[kw80]

A workaround is using labels instead
runs-on: myLabel
instead of

runs-on:
  group: myRunnerGroup

[MaheswariS03]

Removing runner group from definition works however our env consists of multiple GH apps used by different teams and we rely on groups to distinguish between runners.