As a workaround, additional code must be inserted into the SPF module /usr/share/grommunio-antispam/lualib/lua_ffi/spf.lua below local ffi = require 'ffi' to ensure that the shared module lua_ffi.common is explicitly loaded:
Edit: /usr/share/grommunio-antispam/lualib/lua_ffi/spf.lua and add the line: require 'lua_ffi.common'
...
local ffi = require 'ffi'
require 'lua_ffi.common'
...
Restart grommunio-antispam: systemctl restart grommunio-antispam
Run rspamadm configtest. You should not see this error anymore.
# rspamadm configtest
duplicate symbol: JUST_EICAR, skip registering
duplicate symbol: CHECK_MID, skip registering
trying to add virtual symbol MID_BARE_IP as real (no parent)
trying to add virtual symbol MID_RHS_NOT_FQDN as real (no parent)
trying to add virtual symbol MID_MISSING_BRACKETS as real (no parent)
trying to add virtual symbol MID_RHS_IP_LITERAL as real (no parent)
trying to add virtual symbol MID_CONTAINS_FROM as real (no parent)
trying to add virtual symbol MID_RHS_MATCH_FROM as real (no parent)
trying to add virtual symbol MID_RHS_MATCH_FROMTLD as real (no parent)
trying to add virtual symbol MID_CONTAINS_TO as real (no parent)
trying to add virtual symbol MID_RHS_MATCH_TO as real (no parent)
duplicate symbol: MID_END_EQ_FROM_USER_PART, skip registering
syntax OK
Enjoy grommunio
