>50 second delay on arrival of inbound calls: iNum/sipbroker & with/without firewall
 

A Voxalot account is used on a "Acrobits Softphone Business/1.4" User-Agent, running on iPhone OS4.1.

The configuration has been set to:
domain: eu.voxalot.com
transport protocol: udp
proxy: eu.voxalot.com:5060
stun: 202.60.88.238:3478
discover global ip: off
expires: 3599

Calls setup via both (a) a firewalled and (b) a non-firewalled network, using :
(c) iNum connectivity +883 5100 04 <voxalot account number>
and
(d) Sipbroker connectivity *031 <voxalot account number>
arrive with 50 second delays or longer.

Neither the "Symmetric NAT Handling": yes/no does shorten the delay.

Possible cause: One thing I can image is that the device has multiple registrations at voxalot, which are not visible in http://www.voxalot.com/action/deviceRegistrations where only a single registration is shown. Despite that in the background multiple unexpired (hidden) registrations are listed, where voxalot starts delivering at the oldest instead of the newest registration. This happens to me when using bluesip.net with the Groundwire user agent.

How likely can this "multiple (hidden) registrations" be the cause for long delays on inbound calls arriving at the user agent?
Or what else could be the problem?

PS My account is NOT my forumname.