fixed issue on udpstreamer trigger logic

Client/udpscope/FrameDecoder.h

@@ -58,11 +58,15 @@
  * CONSUMING signal, where UDPSourceSession.cpp:538 and :516 key it on the
  * time-signal index, so signals sharing a time signal share an offset there and
  * not here — immaterial, since the mapping they compute is the same. And a
- * FIRST_SAMPLE/LAST_SAMPLE signal whose time signal is absent falls through to
- * rule 4 rather than using its declared rate; that is a malformed CONFIG, and
- * spanning arrivals is the more honest answer than trusting a rate whose anchor
- * never arrived. Neither this list nor the three above is closed: any other
- * difference you find is unexamined, not sanctioned.
+ * FIRST_SAMPLE/LAST_SAMPLE signal of DECLARED ARRAY shape whose time signal is
+ * absent falls through to rule 4 rather than using its declared rate; that is a
+ * malformed CONFIG, and spanning arrivals is the more honest answer than
+ * trusting a rate whose anchor never arrived. Note the shape qualifier: an
+ * accumulated SCALAR is declared with one element, so a frame that carries no
+ * time signal for it routes to rule 3, which does use the declared rate — the
+ * normal case, since Accumulate flushes per signal on a timer. Neither this list
+ * nor the three above is closed: any other difference you find is unexamined,
+ * not sanctioned.
  */
 #pragma once
 
@@ -100,7 +104,16 @@ private:
                      std::vector<double>& tsOut);
 
     struct SigState {
+        /** Rules 1 and 2: maps the TIME SIGNAL's epoch onto the wall clock. */
         ClockOffset offset;
+        /** Rule 3's hrt branch, which maps a different epoch — accProdSec counts
+         *  from this signal's first usable packet, not from whatever zero the
+         *  time signal uses. One signal can reach both: a declared scalar with
+         *  FIRST_SAMPLE takes rule 2 in frames where its time signal carries an
+         *  element and rule 3 in frames where it does not, which Accumulate's
+         *  per-signal timer flushing makes ordinary. Sharing one ClockOffset
+         *  across the two forces a re-latch on every alternation. */
+        ClockOffset accOffset;
         double      lastPacketWall  = 0.0;
         bool        lastPacketValid = false;
         /** Raw ticks, not seconds — see the comment in the samplingRate == 0