asterisk users - Sep 2019 - IPv4 address in SDP o= is (null) when configured for NAT using pjsip

Using Asteirsk 13.28.1:

If I configure my pjsip transport to handle NAT from the Internet:

[transport-tcp]
type=transport
protocol=tcp
bind=10.75.22.8:5060
local_net=10.75.22.0/24
external_media_address=[external address redacted]
external_signaling_address=[external address redacted]

When a call comes from a TCP registered SIP client on the Internet,
Asterisk is setting the IPv4 address in the "o=" and "c="
lines of the
SDP ICE payload to "(null)":

v=0
o=- 3654 548 IN IP4 (null)
s=Asterisk
c=IN IP4 (null)

IPv4 addresses in all of the a= lines are still correct.

This "(null)" of course causes the caller to fail to complete the
call.

Is there something more I have to do to have Asterisk/pjsip properly
set the IPv4 address in the SDP ICE payloads?

Cheers,
b.

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