Has anyone experienced MCS-1001 with GitHub-based Copilot Agents after Aug 31?

Question

I'm seeing a strange issue and would like to know if anyone else is experiencing the same problem.

Current status:

• CIRA Ai Assistant Rev1.0 (created with the Standard Agent platform) works normally in both Microsoft 365 Copilot and Teams.
• CIRA Ai Assistant Rev2.0 (created with the GitHub Agent platform) can be opened and tested successfully in the Copilot Studio test environment, but cannot be opened in either Microsoft 365 Copilot or Teams.

Teams error:

MCS-1001 (SystemError)

Timeline:

• Worked normally before Aug 31, 2026
• Stopped working after Aug 31, 2026
• Still works in Copilot Studio test environment

Comparison:

Agent	Platform	Copilot Studio	M365 Copilot	Teams
Rev1.0	Standard Agent	✅	✅	✅
Rev2.0	GitHub Agent	✅	❌	❌

Has anyone seen similar behavior recently, especially with GitHub-based agents? I'm trying to determine whether this is a service-side issue, a GitHub Agent migration issue, or something tenant-specific.

Thanks!I'm seeing a strange issue and would like to know if anyone else is experiencing the same problem.

Current status:

• CIRA Ai Assistant Rev1.0 (created with the Standard Agent platform) works normally in both Microsoft 365 Copilot and Teams.
• CIRA Ai Assistant Rev2.0 (created with the GitHub Agent platform) can be opened and tested successfully in the Copilot Studio test environment, but cannot be opened in either Microsoft 365 Copilot or Teams.

Teams error:

MCS-1001 (SystemError)

Timeline:

• Worked normally before Aug 31, 2026
• Stopped working after Aug 31, 2026
• Still works in Copilot Studio test environment

Comparison:

Agent	Platform	Copilot Studio	M365 Copilot	Teams
Rev1.0	Standard Agent	✅	✅	✅
Rev2.0	GitHub Agent	✅	❌	❌

Has anyone seen similar behavior recently, especially with GitHub-based agents? I'm trying to determine whether this is a service-side issue, a GitHub Agent migration issue, or something tenant-specific.

Thanks!