what we are finding so far is once you reach the last call-sign like Pontiac 9-1 or Jedi 9-1 then no more can be created and it throws this error with a rotating hour glass, Russian units are not effected by this as they use a numbering call-sign system, but no one so far is having a problem with just older missions unless they have very large numbers of units and reach the group ID of 9
DEBUG LuaGUI (Main): error, can not create new callsign, groupId > 9