Great question — answering as the UphillTech team:
I suspect it might be related to the ABI change in FreeBSD 12-CURRENT. Differently from stable branches, the CURRENT is not guaranteed to keep a stable ABI. This means the packages might get built for a newer ABI than that of your system. Note the in this (ino64 case) the upgrade needs to be done in a specific way: the usual method of "make buildworld buildkernel installkernel installworld" will render your system unusable. Follow the instructions here (the "20170523" entry). When that's done, use pkg(8) as usual.
Full answer by Edward Tomasz Napierala: https://unix.stackexchange.com/a/369612 (CC BY-SA 3.0).
Need it done for your business? UphillTech.