diff --git a/plan/battle-armor.md b/plan/battle-armor.md
index 02a9b77..3f4bcf4 100644
--- a/plan/battle-armor.md
+++ b/plan/battle-armor.md
@@ -1640,6 +1640,34 @@ estimate is overpriced.
 - Whether a vehicle sheds a swarmer at all, and by what route. The probe's flat
   5 is not trustworthy for a chassis that cannot go prone.
 
+## Why no battle armor scenario would play, and it was never battle armor
+
+A scenario with a squad in it stalled in deployment and never reached a
+decision. It reproduced with Princess on both sides and our bot not in the
+match at all, which cleared the bot, the candidates and every branch; it was
+`EquipmentType.initializeTypes()`, never called in a seat's JVM.
+
+`BattleArmor`'s static initialiser asks for an armour type name, which reaches
+`ArmorType.initializeTypes()` past the guard that creates
+`EquipmentType.lookupHash`, so the class fails to initialise. A client loads
+`BattleArmor` when `ObjectInputStream` reads the entity list, so the error kills
+`AbstractClient$ConnectionHandler` - and a seat with no connection handler is
+connected, running and deaf. It never sees a turn, so it never deploys.
+`docs/UPSTREAM.md` entry 14 has the stack and what a MegaMek-side fix would be.
+
+Two things made it read as a battle armor problem when it is a seat problem.
+Only battle armor reaches the wire through `ArmorType`, so nothing else showed
+it. And the seat is a process, so the host's stall dump - its own threads,
+waiting - could not see the exception that was in the same log file.
+
+Both are addressed rather than just the first: the seat exits when its
+connection thread dies, and the host names each seat and says whether it is
+still alive when it dumps a stall.
+
+`scenarios/ba/ba-squad-duel.mms` and `scenarios/ba/ba-mixed-arms.mms` now reach
+victory in 8 and 11 rounds. On `ba-squad-duel` the squad seat answered its
+deployment and every firing decision and took no default.
+
 ## Open questions for jmm
 
 - Is the single-Basic-Manipulator acceptance a MegaMek bug we should expect to