diff --git a/jfj-combined/include/JfjFrameCache.hpp b/jfj-combined/include/JfjFrameCache.hpp
index 0207d14..cc226ca 100644
--- a/jfj-combined/include/JfjFrameCache.hpp
+++ b/jfj-combined/include/JfjFrameCache.hpp
@@ -31,7 +31,7 @@ public:
             f_send(callback), m_lock(_C), m_valid(_C) {
         // Initialize buffer metadata
         for(auto& it: m_buffer){ memset(&it.meta, 0, sizeof(it.meta)); }
-        
+
         // Initialize Mutexes
         for(auto& it: m_valid){ it = 0; }
     };
@@ -41,25 +41,24 @@ public:
 
     Place a recorded frame to it's corresponding module location.
     This simultaneously handles buffering and assembly. **/
-    void emplace(uint64_t pulseID, uint64_t moduleIDX, BufferBinaryFormat& ref_frame){
+    void emplace(uint64_t pulseID, uint64_t moduleIDX, BufferBinaryFormat& inc_frame){
         uint64_t idx = pulseID % m_CAP;
-        
-        // A new frame is starting
-        if(ref_frame.meta.pulse_id != m_buffer[idx].meta.pulse_id){
-            start_line(idx, ref_frame.meta);
-        }        
-        
-        // Shared lock for concurrent PUT operations
-        std::shared_lock<std::shared_mutex> guard(m_lock[idx]);
 
-        // Copy metadata (manually for now...)
-        m_buffer[idx].meta.pulse_id = ref_frame.meta.pulse_id;
-        m_buffer[idx].meta.frame_index = ref_frame.meta.frame_index;
-        m_buffer[idx].meta.daq_rec = ref_frame.meta.daq_rec;
-        
+        // A new frame is starting
+        if(inc_frame.meta.pulse_id != m_buffer[idx].meta.pulse_id){
+            std::unique_lock<std::shared_mutex> p_guard(m_lock[idx]);
+            // Check if condition persists after getting the mutex
+            if(inc_frame.meta.pulse_id != m_buffer[idx].meta.pulse_id){
+                start_line(idx, inc_frame.meta);
+            }
+        }
+
+        // Shared lock for concurrent PUT operations
+        std::shared_lock<std::shared_mutex> s_guard(m_lock[idx]);
+
         // Calculate destination pointer (easier to debug)
         char* ptr_dest = m_buffer[idx].data.data() + moduleIDX * m_blocksize;
-        std::memcpy((void*)ptr_dest, (void*)&ref_frame.data, m_blocksize);
+        std::memcpy((void*)ptr_dest, (void*)&inc_frame.data, m_blocksize);
     }
 
     void flush_all(){
@@ -78,17 +77,16 @@ public:
     }
 
     // Flush and start a new line (incl. lock)
-    void start_line(uint64_t idx, ModuleFrame& ref_meta){
+    void start_line(uint64_t idx, ModuleFrame& inc_frame){
         // 0. Guard
-        std::unique_lock<std::shared_mutex> guard(m_lock[idx]);
         // 1. Flush
         if(m_valid[idx]){
              f_send(m_buffer[idx]);
         }
         // 2. Init
-        m_buffer[idx].meta.pulse_id = ref_meta.pulse_id;
-        m_buffer[idx].meta.frame_index = ref_meta.frame_index;
-        m_buffer[idx].meta.daq_rec = ref_meta.daq_rec;
+        m_buffer[idx].meta.pulse_id = inc_frame.pulse_id;
+        m_buffer[idx].meta.frame_index = inc_frame.frame_index;
+        m_buffer[idx].meta.daq_rec = inc_frame.daq_rec;
         m_buffer[idx].meta.is_good_image = true;
         m_valid[idx] = 1;
     }