[Help] sip outbound re-registration blocks incoming requests

I have multiple register=> commands in sip.conf, I am running * 1.2.13, same behaviour with previous 1.2.x

Everthing works fine except for some reasons, it blocks any incoming SIP messages (eg INVITE, NOTIFY) during outbound re-registrations of those SIP providers I have setup. Once ALL the re-registrations are done, I can see a flood of debug sip messages appearing on console/log.

sip show registry:
Host Username Refresh State
freespeech.co.uk:5060 08444123456 105 Request Sent
sipgate.co.uk:5060 9991234 105 Request Sent
sipgate.co.uk:5060 1236789 105 Request Sent
sipgate.co.uk:5060 1001234 105 Request Sent 85235021234 105 Registered
s2hkbntel.net:5060 33221234hk 95 Registered

I cannot make any outgoing calls when the re-registration happens, which is once every 1-2 minutes.

Anyone seen this before? Anything I’m doing wrong?

Thanks in advance,