While https://community.bistudio.com/wiki/Arma_3:_CfgRemoteExec states
As usual, the more local config takes precedence: Mission Description.ext (missionConfigFile) > Campaign Description.ext (campaignConfigFile) > Game / Mod Config (configFile). If several definitions for CfgRemoteExec exist, the mode attribute will be overridden by the last parsed config and whitelisted functions and commands will be merged.
This makes sense for mode/jip parameter or when a function/command is defined in both mod and mission, yet otherwise function/command definitions from a mod should not be invalidated
Server.rpt
Scripting function 'bis_fnc_execvm' is not allowed to be remotely executed
User NAME (DDD) tried to remoteExec a disabled functionScripting function 'xxx_fnc_modFuncution_test' is not allowed to be remotely executed
Client.rpt
Scripting command 'say3d' is not allowed to be remotely executed
Scripting function 'xxx_fnc_modFuncution_test' is not allowed to be remotely executed