diff --git a/src/core/timer_system.cpp b/src/core/timer_system.cpp
index 8e5b44798..1ebe419c5 100644
--- a/src/core/timer_system.cpp
+++ b/src/core/timer_system.cpp
@@ -88,15 +88,19 @@ void TimerSystem::OnLevelEnd()
     m_has_map_ticked = false;
 }
 
-void TimerSystem::OnStartupServer()
+void TimerSystem::OnStartupServer(bool levelShutdown)
 {
-    if (m_has_map_ticked)
+    if (levelShutdown && m_has_map_ticked)
     {
         CALL_GLOBAL_LISTENER(OnLevelEnd());
 
         CSSHARP_CORE_TRACE("name={0}", "LevelShutdown");
     }
 
+    // Reset is UNCONDITIONAL -- universal_time math in OnGameFrame depends on
+    // m_has_map_ticked being false on the first frame of every new session,
+    // whether that session came in via a genuine LevelShutdown or a workshop
+    // ss_dead reload.
     m_has_map_ticked = false;
     m_has_map_simulated = false;
 }
diff --git a/src/core/timer_system.h b/src/core/timer_system.h
index 4a9a28a44..5b6ec3cdb 100644
--- a/src/core/timer_system.h
+++ b/src/core/timer_system.h
@@ -72,7 +72,14 @@ class TimerSystem : public GlobalClass
     void OnShutdown() override;
     void OnLevelEnd() override;
     void OnGameFrame(bool simulating);
-    void OnStartupServer();
+    // levelShutdown=true on a genuine OnLevelShutdown -> OnStartupServer sequence
+    // (real changelevel/shutdown). levelShutdown=false on workshop ss_dead reload
+    // cycles that fire Hook_StartupServer without OnLevelShutdown -- in that case
+    // we must NOT fire OnLevelEnd (PlayerManager disconnects still-connected
+    // players -> stale .NET callbacks -> SEGV on the next DispatchConCommand
+    // hook), but we MUST still reset the per-map tick state for universal_time
+    // math to stay correct across the cycle.
+    void OnStartupServer(bool levelShutdown);
     double CalculateNextThink(double last_think_time, float interval);
     void RunFrame();
     void RemoveMapChangeTimers();
diff --git a/src/mm_plugin.cpp b/src/mm_plugin.cpp
index 1c611badc..4bf19725a 100644
--- a/src/mm_plugin.cpp
+++ b/src/mm_plugin.cpp
@@ -204,12 +204,29 @@ bool CounterStrikeSharpMMPlugin::Load(PluginId id, ISmmAPI* ismm, char* error, s
     return true;
 }
 
+static bool s_bLevelShutdownOccurred = false;
+
 void CounterStrikeSharpMMPlugin::Hook_StartupServer(const GameSessionConfiguration_t& config, ISource2WorldSession*, const char*)
 {
     globals::entitySystem = interfaces::pGameResourceServiceServer->GetGameEntitySystem();
+    // Remove before adding to prevent double-registration when workshop addon changes
+    // trigger a second StartupServer within the same map session (ss_dead cycle).
+    globals::entitySystem->RemoveListenerEntity(&globals::entityManager.entityListener);
     globals::entitySystem->AddListenerEntity(&globals::entityManager.entityListener);
 
-    globals::timerSystem.OnStartupServer();
+    // Workshop ss_dead reload cycles fire Hook_StartupServer without a
+    // preceding OnLevelShutdown. We pass that distinction down so that:
+    //   levelShutdown=true  -> fires OnLevelEnd (PlayerManager etc.) and
+    //                          resets timer tick state. Genuine changelevel.
+    //   levelShutdown=false -> ONLY resets timer tick state. No OnLevelEnd,
+    //                          which is what avoids the PlayerManager
+    //                          disconnect -> stale .NET callbacks -> SEGV
+    //                          chain on ss_dead reloads.
+    // Tick-state reset must be unconditional so universal_time math in
+    // OnGameFrame doesn't desync across the cycle (otherwise pending one-off
+    // timers stall arbitrarily long).
+    globals::timerSystem.OnStartupServer(s_bLevelShutdownOccurred);
+    s_bLevelShutdownOccurred = false;
 
     on_activate_callback->ScriptContext().Reset();
     on_activate_callback->ScriptContext().Push(globals::getGlobalVars()->mapname.ToCStr());
@@ -299,7 +316,7 @@ int CounterStrikeSharpMMPlugin::Hook_LoadEventsFromFile(const char* filename, bo
     RETURN_META_VALUE(MRES_IGNORED, 0);
 }
 
-void CounterStrikeSharpMMPlugin::OnLevelShutdown() {}
+void CounterStrikeSharpMMPlugin::OnLevelShutdown() { s_bLevelShutdownOccurred = true; }
 
 bool CounterStrikeSharpMMPlugin::Pause(char* error, size_t maxlen) { return true; }