What do you mean by "not seeming to fire"? You don't get CharacterEnteredTrigger events for your subregion triggers? If the issue is that you don't get the "sign" near the top of the screen that you entered the subregion: that's because the last parameter of your DB_Subregion() fact definition is 0 instead of 1. 0 means "don't show anything when entering", 1 means "show a sign when entering using the translated string with the specified key".
Really? I thought those markers were the flag map markers on the player map. My UI notifications all appear with the floating banner when using 0 in the DB assignment. For instance, this gives me the "Iolo's Hut" banner when entering the region:
DB_Subregion(TRIGGERGUID_TRG_Moon_Iolo_hut_09b43f5f-278c-409a-9aaa-bf31b7364538, "LVL_SUB_IOLOS_HUT", 0);
