Remote extensions re registering every 60 seconds from different ports, dont ring for incoming calls

Hey gang, hoping to get some input on a problem I can’t seem to find much on.
Switched from Vonage and factory reset some Polycom 335s. Used FreePBX Endpoint Manager to provision all extensions, and we have 3 extensions in a remote building that aren’t ringing for incoming calls. They can call out with no issues, the system ‘thinks’ they are ringing when you call them (you aren’t forwarded to voicemail or follow me) but the phone itself doesnt ring. show peers show them as OK and reachable, but I’m seeing these 3 extensions all registering every 60 seconds on different ports everytime (See Below). Firewall has no SIP transformation, could it be something to do with the Polycom provisioning? Or should I try tweaking something in FreePBX sip settings?

[2015-08-31 03:09:28] VERBOSE[11458] chan_sip.c:     -- Registered SIP '117' at my.remote.ip.address:10367
[2015-08-31 03:09:31] VERBOSE[11458] chan_sip.c:     -- Registered SIP '114' at my.remote.ip.address:36832
[2015-08-31 03:09:37] VERBOSE[11458] chan_sip.c:     -- Registered SIP '113' at my.remote.ip.address:44262
[2015-08-31 03:10:28] VERBOSE[11458] chan_sip.c:     -- Registered SIP '117' at my.remote.ip.address:39894
[2015-08-31 03:10:31] VERBOSE[11458] chan_sip.c:     -- Registered SIP '114' at my.remote.ip.address:64499
[2015-08-31 03:10:37] VERBOSE[11458] chan_sip.c:     -- Registered SIP '113' at my.remote.ip.address:20950

This sounds like a NAT/Firewall issue on the remote end.

You’re exactly right, the ‘it guy’ assured me there was no firewall there but I went over there and sure enough they had a SonicWall TZ105 sitting there!