ofc, New arguments.

code/datums/diseases/_disease.dm

@@ -35,7 +35,6 @@
 	var/copy_type = null //if this is null, copies will use the type of the instance being copied
 
 /datum/disease/New(make_typecache = TRUE)
-	..()
 	if(make_typecache && length(viable_mobtypes))
 		viable_mobtypes = typecacheof(viable_mobtypes)
 

code/datums/diseases/advance/advance.dm

@@ -80,7 +80,8 @@
 
  */
 
-/datum/disease/advance/New()
+/datum/disease/advance/New(make_typecache = TRUE)
+	..()
 	Refresh()
 
 /datum/disease/advance/Destroy()

code/datums/diseases/advance/presets.dm

@@ -2,7 +2,7 @@
 /datum/disease/advance/cold
 	copy_type = /datum/disease/advance
 
-/datum/disease/advance/cold/New()
+/datum/disease/advance/cold/New(make_typecache = TRUE)
 	name = "Cold"
 	symptoms = list(new/datum/symptom/sneeze)
 	..()
@@ -11,7 +11,7 @@
 /datum/disease/advance/flu
 	copy_type = /datum/disease/advance
 
-/datum/disease/advance/flu/New()
+/datum/disease/advance/flu/New(make_typecache = TRUE)
 	name = "Flu"
 	symptoms = list(new/datum/symptom/cough)
 	..()
@@ -21,7 +21,7 @@
 	name = "Experimental Disease"
 	copy_type = /datum/disease/advance
 
-/datum/disease/advance/random/New(max_symptoms, max_level = 8)
+/datum/disease/advance/random/New(make_typecache = TRUE, max_symptoms, max_level = 8)
 	if(!max_symptoms)
 		max_symptoms = rand(1, VIRUS_SYMPTOM_LIMIT)
 	var/list/datum/symptom/possible_symptoms = list()
@@ -37,6 +37,6 @@
 		if(chosen_symptom)
 			var/datum/symptom/S = new chosen_symptom
 			symptoms += S
-	Refresh()
 
-	name = "Sample #[rand(1,10000)]"
+	name = "Sample #[rand(1,10000)]"
+	..()

code/datums/diseases/retrovirus.dm

@@ -13,7 +13,7 @@
 	stage_prob = 2
 	var/restcure = 0
 
-/datum/disease/dna_retrovirus/New()
+/datum/disease/dna_retrovirus/New(make_typecache = TRUE)
 	..()
 	agent = "Virus class [pick("A","B","C","D","E","F")][pick("A","B","C","D","E","F")]-[rand(50,300)]"
 	if(prob(40))