Discovery/Sync o365 - EXO 3.9 breaks poweshell calls

Recently released Microsoft EXO v3.9 breaks powershell calls used by Discovery and Sync, resulting in the below error¹.

To resolve this error, please install EXO v3.5.0 as outlined in Special Office 365 System Requirements

[1] The error below will appear in the log:

Starting Powershell process : 11/26/25 09:01:44  
*************************** Powershell Environment ***************************  
exo version=3.9.0  
powershell version=7.4.0  
****************************************************************************** 

 Powershell Error Crit          | Unknown Status: Unexpected 
Error: 0xffffffff80070520  
Context: (pii)  
Tag: 0x21420087 (error code -2147023584) (internal error code 557973639)  

 Powershell Err Msg             | No Output  

Run Summary : 11/26/25 09:01:57  
 Run Time                       | 14 seconds  

Error Summary : 11/26/25 09:01:57  
 Powershell Error               | 1  
 Fatal Error                    | 1  

#Ref: 3-36-3