This issue occurs even if the values of the system workload management (WLM) are overridden by using the New-SettingOverride command. System continues to use default values for on-premises installations in a Microsoft Exchange Server 2013 environment that has Cumulative Update 6 or a later version update installed.
This issue occurs because of a by design logic in the Exchange Server 2013 environment.
To resolve this issue, install Cumulative Update 9 for Exchange Server 2013.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about Exchange Server 2013 workload management, see Workload Management in Exchange 2013.