diff --git a/wled00/bus_manager.cpp b/wled00/bus_manager.cpp
index e8b2b40b..1f75410e 100644
--- a/wled00/bus_manager.cpp
+++ b/wled00/bus_manager.cpp
@@ -1272,7 +1272,6 @@ int BusManager::add(BusConfig &bc) {
   lastlen = 0;
   laststart = 0;
   lastBus = nullptr;
-  slowMode = false;
 
   DEBUG_PRINTF("BusManager::add(bc.type=%u)\n", bc.type);
   if (bc.type >= TYPE_NET_DDP_RGB && bc.type < 96) {
@@ -1293,6 +1292,34 @@ int BusManager::add(BusConfig &bc) {
   } else {
     busses[numBusses] = new BusPwm(bc);
   }
+
+  // WLEDMM ToDO
+  Bus *newBus = busses[numBusses];
+  unsigned newStart = newBus->getStart();
+  unsigned newEnd = newStart + newBus->getLength() - 1;
+  // WLEDMM check if added bus overlaps with any existing bus
+  bool foundOverlap = false;
+  unsigned busCount = getNumBusses();
+  if (newBus != nullptr && newBus->isOk()) {
+    for (unsigned i=0; i<busCount; i++) {
+      if (i == numBusses) continue; // skip self - should not happen
+      Bus *theBus = getBus(i);
+      if (theBus == nullptr) continue;
+      if (!theBus->isOk()) continue;
+      // check for overlap
+      unsigned theStart = theBus->getStart();
+      unsigned theEnd = theStart + theBus->getLength() - 1;
+      // see https://stackoverflow.com/questions/3269434/whats-the-most-efficient-way-to-test-if-two-ranges-overlap
+      if ((newStart <= theEnd) && (theStart <= newEnd)) {  // catches all overlap scenarios - including "new is including (around) another range"
+        foundOverlap = true;  
+        USER_PRINTF("bus %u[%u %u] overlaps with\t%u [%u %u]", numBusses, newStart, newEnd, i, theStart, theEnd);
+      }
+    }
+  }
+  // if some busses overlap, we disable the bus caching optimization to allow multiple outputs for the same pixel
+  if (foundOverlap) { overlapingBusses = true; slowMode = true; }
+  if (numBusses < 1) { overlapingBusses = false; slowMode = false; }
+  USER_PRINT(slowMode ? "busses are in SlowMode\n" : "");
   return numBusses++;
 }
 
@@ -1312,6 +1339,7 @@ void BusManager::removeAll() {
   laststart = 0;
   lastlen = 0;
   slowMode = false;
+  overlapingBusses = false;
 }
 
 void __attribute__((hot)) BusManager::show() {
@@ -1431,7 +1459,7 @@ uint32_t IRAM_ATTR  __attribute__((hot)) BusManager::getPixelColorRestored(uint_
 
 bool BusManager::canAllShow() const {
   for (uint8_t i = 0; i < numBusses; i++) {
-    if (!busses[i]->canShow()) return false;
+    if ((busses[i]->isOk()) && !busses[i]->canShow()) return false;
   }
   return true;
 }
diff --git a/wled00/bus_manager.h b/wled00/bus_manager.h
index ea886eaf..23a3d221 100644
--- a/wled00/bus_manager.h
+++ b/wled00/bus_manager.h
@@ -373,7 +373,7 @@ class BusNetwork : public Bus {
       return _artnet_leds_per_output;
     }
 
-    void setColorOrder(uint8_t colorOrder);
+    void setColorOrder(uint8_t colorOrder); // ??? not implemented???
 
     uint8_t getColorOrder() const override {
       return _colorOrder;
@@ -464,7 +464,7 @@ class BusManager {
       lastBus = nullptr;
       laststart = 0;
       lastlen= 0;
-      slowMode = isRTMode;
+      if (isRTMode || !overlapingBusses) slowMode = isRTMode; // don't reset slowMode if we have overlaping busses
     }
 
     void setStatusPixel(uint32_t c);
@@ -507,6 +507,7 @@ class BusManager {
     unsigned laststart = 0;
     unsigned lastlen = 0;
     bool slowMode = false; // WLEDMM not sure why we need this. But its necessary.
+    bool overlapingBusses = false; // WLEDMM needed to enforce "slowMode" when busses overlap (=custom bus start indices)
 
     inline uint8_t getNumVirtualBusses() const {
       int j = 0;