diff --git a/LEGO1/lego/legoomni/include/infocenter.h b/LEGO1/lego/legoomni/include/infocenter.h
index 7749cc84..d54540dd 100644
--- a/LEGO1/lego/legoomni/include/infocenter.h
+++ b/LEGO1/lego/legoomni/include/infocenter.h
@@ -50,6 +50,9 @@ class InfocenterState : public LegoState {
 
 	void SetUnknown0x74(MxU32 p_unk0x74) { m_unk0x74 = p_unk0x74; }
 
+	// FUNCTION: BETA10 0x10031bd0
+	MxBool FirstLetterIsNotNull() { return m_letters[0] != NULL; }
+
 	// SYNTHETIC: LEGO1 0x10071900
 	// InfocenterState::`scalar deleting destructor'
 
diff --git a/LEGO1/lego/legoomni/include/registrationbook.h b/LEGO1/lego/legoomni/include/registrationbook.h
index 3e2cf367..146bcf30 100644
--- a/LEGO1/lego/legoomni/include/registrationbook.h
+++ b/LEGO1/lego/legoomni/include/registrationbook.h
@@ -40,7 +40,7 @@ class RegistrationBook : public LegoWorld {
 	MxBool Escape() override;                         // vtable+0x64
 	void Enable(MxBool p_enable) override;            // vtable+0x68
 
-	inline void PlayAction(MxU32 p_objectId);
+	inline static void PlayAction(MxU32 p_objectId);
 
 	// SYNTHETIC: LEGO1 0x10076f30
 	// RegistrationBook::`scalar deleting destructor'
diff --git a/LEGO1/lego/legoomni/src/worlds/registrationbook.cpp b/LEGO1/lego/legoomni/src/worlds/registrationbook.cpp
index 7787ccd5..9a0eae9a 100644
--- a/LEGO1/lego/legoomni/src/worlds/registrationbook.cpp
+++ b/LEGO1/lego/legoomni/src/worlds/registrationbook.cpp
@@ -268,6 +268,7 @@ MxLong RegistrationBook::HandleControl(LegoControlManagerNotificationParam& p_pa
 }
 
 // FUNCTION: LEGO1 0x100775c0
+// STUB: BETA10 0x100f32b2
 void RegistrationBook::FUN_100775c0(MxS16 p_playerIndex)
 {
 	if (m_infocenterState->HasRegistered()) {
@@ -391,6 +392,10 @@ void RegistrationBook::FUN_100778c0()
 // FUNCTION: BETA10 0x100f3671
 void RegistrationBook::ReadyWorld()
 {
+	// This function is very fragile and appears to oscillate between two versions on small changes.
+	// This even happens for commenting out `assert()` calls, which shouldn't affect release builds at all.
+	// See https://github.com/isledecomp/isle/pull/1375 for a version that had 100 %.
+
 	LegoGameState* gameState = GameState();
 	gameState->m_history.WriteScoreHistory();
 
@@ -405,6 +410,7 @@ void RegistrationBook::ReadyWorld()
 		if (i < 26) {
 			m_alphabet[i] = (MxStillPresenter*) Find("MxStillPresenter", letterBuffer);
 			assert(m_alphabet[i]);
+
 			// We need to loop through the entire alphabet,
 			// so increment the first char of the bitmap name
 			letterBuffer[0]++;
@@ -416,6 +422,7 @@ void RegistrationBook::ReadyWorld()
 	for (i = 0; i < 10; i++) {
 		m_checkmark[i] = (MxControlPresenter*) Find("MxControlPresenter", checkmarkBuffer);
 		assert(m_checkmark[i]);
+
 		// Just like in the prior letter loop,
 		// we need to increment the fifth char
 		// to get the next checkmark bitmap
@@ -444,7 +451,15 @@ void RegistrationBook::ReadyWorld()
 		}
 	}
 
-	if (m_infocenterState->m_letters[0] != NULL) {
+#ifdef BETA10
+	InfocenterState* infocenterState = (InfocenterState*) GameState()->GetState("InfocenterState");
+	assert(infocenterState);
+
+	if (infocenterState->FirstLetterIsNotNull())
+#else
+	if (m_infocenterState->FirstLetterIsNotNull())
+#endif
+	{
 		PlayAction(RegbookScript::c_iic008in_PlayWav);
 
 		LegoROI* infoman = FindROI(g_infoman);
@@ -457,6 +472,7 @@ void RegistrationBook::ReadyWorld()
 	}
 }
 
+// FUNCTION: BETA10 0x100f3424
 inline void RegistrationBook::PlayAction(MxU32 p_objectId)
 {
 	MxDSAction action;