diff --git a/EllesmereUIRaidFrames/EllesmereUIRaidFrames.lua b/EllesmereUIRaidFrames/EllesmereUIRaidFrames.lua
index f86dcffa..afda1668 100644
--- a/EllesmereUIRaidFrames/EllesmereUIRaidFrames.lua
+++ b/EllesmereUIRaidFrames/EllesmereUIRaidFrames.lua
@@ -7732,7 +7732,8 @@ XF.EnsureBuilt = function(count)
             elseif event == "UNIT_THREAT_LIST_UPDATE" or event == "UNIT_THREAT_SITUATION_UPDATE" then
                 local d = GetFFD(b)
                 if d.threatFrame then
-                    local bs = db.profile.threatBorderSize or 0
+                    local s = d._isExtra and ns._scaledExtraProxy or ns._scaledProfile
+                    local bs = s.threatBorderSize or 0
                     if bs > 0 then
                         local status = UnitThreatSituation(unit)
                         if status and THREAT_ACTIVE[status] and PP then
@@ -10297,7 +10298,8 @@ local function OnEvent(self, event, arg1, ...)
         if btn then
             local d = GetFFD(btn)
             if d.threatFrame then
-                local bs = db.profile.threatBorderSize or 0
+                local s = d._isParty and ns._scaledPartyProxy or (d._isExtra and ns._scaledExtraProxy) or ns._scaledProfile
+                local bs = s.threatBorderSize or 0
                 if bs > 0 then
                     local status = UnitThreatSituation(arg1)
                     if status and THREAT_ACTIVE[status] and PP then
@@ -10539,6 +10541,8 @@ do
             "customBgColor", "bgClassColored", "bgDarkness", "smoothBars",
             "healPrediction", "healPredOpacity", "healPredColor",
             "healthVerticalFill",
+            -- Drawn as "Threat Borders" on the Health Bar row, so it files here.
+            "threatBorderSize",
         },
         absorbs = {
             "absorbStyle", "absorbOpacity", "absorbColor", "absorbEdgeMode", "showOvershield",
@@ -10578,7 +10582,7 @@ do
             "borderBehind", "borderTextureOffset", "borderTextureOffsetY",
             "borderTextureShiftX", "borderTextureShiftY",
             "hoverBorderEnabled", "hoverBorderSize", "hoverBorderColor", "hoverBorderAlpha",
-            "targetBorderEnabled", "targetBorderSize", "targetBorderColor", "targetBorderAlpha", "threatBorderSize",
+            "targetBorderEnabled", "targetBorderSize", "targetBorderColor", "targetBorderAlpha",
         },
         dispels = {
             "dispelBorderSize", "dispelOverlay", "dispelOverlayOpacity", "dispelShowAll",
diff --git a/EllesmereUI_Migration.lua b/EllesmereUI_Migration.lua
index 553a8134..3cb57a25 100644
--- a/EllesmereUI_Migration.lua
+++ b/EllesmereUI_Migration.lua
@@ -4356,3 +4356,46 @@ EllesmereUI.RegisterMigration({
         if type(p) == "table" then p.showCastTarget = false end
     end,
 })
+
+--------------------------------------------------------------------------------
+--  Raid Frames: threatBorderSize moved party-sync sections
+--
+--  The "Threat Borders" slider is drawn on the Health Bar row but the key was
+--  filed under the Indicators party-sync section, so editing it on the Party
+--  tab wrote the shared raid value. The key now files under "healthBar", which
+--  matches where its control lives.
+--
+--  Writing party_threatBorderSize through the UI required both sections custom,
+--  but the legacy showThreat -> slider conversion writes it directly, bypassing
+--  that gate. So the override can be live under one mapping and dormant under
+--  the other, in either direction. Clear it whenever that state would flip: in
+--  the flip-to-live case that preserves exactly what party renders today, and
+--  in the flip-to-dormant case party inherits raid either way while clearing
+--  stops the value reviving later. An override live under BOTH mappings (the
+--  normal both-custom case) is left untouched.
+--------------------------------------------------------------------------------
+EllesmereUI.RegisterMigration({
+    id          = "rf_threat_border_party_section_v2",
+    scope       = "profile",
+    description = "Clear a party threat border override whose live/dormant state would flip when threatBorderSize moved to the Health Bar sync section.",
+    body = function(ctx)
+        local rf = ctx.profile.addons and ctx.profile.addons.EllesmereUIRaidFrames
+        if type(rf) ~= "table" then return end
+        -- Consume the legacy party conversion HERE. ERF:OnInitialize performs
+        -- the same rewrite, but child addons initialize after the parent's
+        -- ADDON_LOADED, so deferring to it would let a dormant 0 land after
+        -- this body had already decided and stamped. Clearing the flag makes
+        -- that later block a no-op; the raid showThreat key is untouched.
+        if rf.party_showThreat ~= nil then
+            if rf.party_showThreat == false then rf.party_threatBorderSize = 0 end
+            rf.party_showThreat = nil
+        end
+        if rf.party_threatBorderSize == nil then return end
+        local ss = type(rf.partySyncSections) == "table" and rf.partySyncSections or nil
+        local wasLive    = (ss and ss.indicators == false) and true or false
+        local willBeLive = (ss and ss.healthBar  == false) and true or false
+        if wasLive ~= willBeLive then
+            rf.party_threatBorderSize = nil
+        end
+    end,
+})