diff --git a/src/sound/s_advsound.cpp b/src/sound/s_advsound.cpp
index f508c187f4..2fd7428b3d 100644
--- a/src/sound/s_advsound.cpp
+++ b/src/sound/s_advsound.cpp
@@ -416,7 +416,7 @@ static int S_AddSound (const char *logicalname, int lumpnum, FScanner *sc)
 
 	sfxid = soundEngine->FindSoundNoHash (logicalname);
 
-	if ((unsigned int)sfxid < S_sfx.Size())
+	if (sfxid > 0 && (unsigned int)sfxid < S_sfx.Size())
 	{ // If the sound has already been defined, change the old definition
 		sfxinfo_t *sfx = &S_sfx[sfxid];
 
@@ -483,7 +483,9 @@ int S_AddPlayerSound (const char *pclass, int gender, int refid,
 
 int S_AddPlayerSound (const char *pclass, int gender, int refid, int lumpnum, bool fromskin)
 {
+
 	auto &S_sfx = soundEngine->GetSounds();
+
 	FString fakename;
 	int id;
 
diff --git a/wadsrc/static/dehsupp.txt b/wadsrc/static/dehsupp.txt
index 8525d11644..59858975f2 100644
--- a/wadsrc/static/dehsupp.txt
+++ b/wadsrc/static/dehsupp.txt
@@ -1199,7 +1199,7 @@ Aliases
 	A_MonsterMeleeAttack, MBF21_MonsterMeleeAttack,
 	A_RadiusDamage,	A_RadiusDamage,
 	A_HealChase,	MBF21_HealChase,
-	A_SeekTracer,	A_SeekerMissile,
+	A_SeekTracer,	MBF21_SeekTracer,
 	A_FindTracer,	A_FindTracer,
 	A_JumpIfHealthBelow, MBF21_JumpIfHealthBelow,
 	A_JumpIfTargetInSight, MBF21_JumpIfTargetInSight,
diff --git a/wadsrc/static/zscript/actors/mbf21.zs b/wadsrc/static/zscript/actors/mbf21.zs
index b6eb4ef892..a8fbd40b3c 100644
--- a/wadsrc/static/zscript/actors/mbf21.zs
+++ b/wadsrc/static/zscript/actors/mbf21.zs
@@ -503,5 +503,11 @@ extend class Weapon
 		player.SetPsprite(PSP_FLASH, tstate);
 	}
 
+	// needed to call A_SeekerMissile with proper defaults.
+	deprecated("2.3", "for Dehacked use only")
+	void MBF21_SeekTracer(int threshold, int turnmax)
+	{
+		A_SeekerMissile(threshold, turnmax);
+	}
 
 }
\ No newline at end of file