I wonder if this IPSEC problem could be the cause of the SIP phone problem I’ve been having. Random phone sets connected through a new, multi-site, all-Mikrotik IPSEC VPN to a PBX in the main office would fail to register inside of 24 hours. Manual reboot of main office router or PBX would fix for a time. So far defeating the SIP helper on the phone connections seems to have fixed the problem. Maybe this IPSEC problem hangs up the SIP helper.
An older but nearly identical configuration at a different business never had this problem. The main difference there is the firmware releases are all 6.7, where this new installation are all 6.13 or 6.15 (main office). In the old installation the SIP helper is enabled on all routers, the default.