Some platforms like to use SIP compact headers to decrease the size of the SIP messages and avoid fragmentation. https://www.ietf.org/rfc/rfc3261.txt

In software 2.29.0 or higher we have implemented the option to enable this feature via auto-provisioning.

ParameterValue
DmGlobal.0.UseCompactSipHeaders

0 = Disabled

1 = Enabled