This is the normal configuration of edb:
Code:
                recruit "roman triarii"  0  requires factions { roman, }  and not marian_reforms 
                recruit "roman legionary cohort ii"  0  requires factions { roman, }  and marian_reforms
To allow the recruitment all along the game, you must delete all the references to the marian_reforms in this way:
Code:
                recruit "roman triarii"  0  requires factions { roman, }  
                recruit "roman legionary cohort ii"  0  requires factions { roman, }
You must do it in all the levels of the buildings where the units appear.