diff --git a/libs/libpredict.lua b/libs/libpredict.lua
index ff046ca2..8f67b7b7 100644
--- a/libs/libpredict.lua
+++ b/libs/libpredict.lua
@@ -134,19 +134,6 @@ local function OnOwnCastStart(spellId, castGUID)
     local amount   = cache[spell_queue[2]][1]
     local casttime = castTime
 
-    if spellName == REGROWTH then
-      local fullSpell = spell_queue[2]
-      local _, _, rankStr = fullSpell and string.find(fullSpell, "Rank (%d+)")
-      local rankNum = rankStr and tonumber(rankStr) or nil
-      if libpredict.sender.regrowth_timer then
-        libpredict.sender.regrowth_target_next = target
-        libpredict.sender.regrowth_rank_next = rankNum
-      else
-        libpredict.sender.regrowth_target = target
-        libpredict.sender.regrowth_rank = rankNum
-      end
-    end
-
     if spellName == PRAYER_OF_HEALING then
       -- target is already correctly set from spell_queue[3]:
       -- selfcast (ALT) = player, otherwise = current target
@@ -207,34 +194,35 @@ local function OnOwnCastSucceeded(spellId, castGUID)
 
   libpredict:HealStop(player)
   local spellName = C_Spell.GetSpellName(spellId)
-  if spellName == REGROWTH then
-    local now = pfUI.uf.now or GetTime()
-    if libpredict.sender.regrowth_timer then
-      libpredict.sender.regrowth_start_next = now
-    else
-      libpredict.sender.regrowth_start = now
-    end
-    libpredict.sender.regrowth_timer = now + 0.1
-  end
   libpredict.sender.castGUID = nil
   libpredict.sender.current_cast = nil
   libpredict.sender.current_cast_target = nil
 
   if not target then return end
 
-  -- Instant HoTs — classify by name (rank-independent) instead of a
-  -- hardcoded per-rank ID table.
+  -- HoTs — classify by name (rank-independent) instead of a hardcoded
+  -- per-rank ID table.
   local hotType
   if spellName == REJUVENATION then hotType = "Reju"
   elseif spellName == RENEW then hotType = "Renew"
+  elseif spellName == REGROWTH then hotType = "Regr"
   end
   if hotType then
-    local duration = hotType == "Reju" and rejuvDuration or renewDuration
     local rank = 0
     local rankSub = C_Spell.GetSpellSubtext(spellId)
     if rankSub and rankSub ~= "" then
       rank = tonumber((string.gsub(rankSub, "Rank ", ""))) or 0
     end
+    if hotType == "Regr" then
+      -- Regrowth's HoT follows its direct heal a moment later
+      local start = GetTime()
+      C_Timer.After(0.1, function()
+        libpredict:Hot(player, target, hotType, 20, start, "UNIT_SPELLCAST_SUCCEEDED", rank)
+        libpredict.sender:SendHealCommMsg(hotType .. "/" .. target .. "/20/" .. rank .. "/")
+      end)
+      return
+    end
+    local duration = hotType == "Reju" and rejuvDuration or renewDuration
     libpredict:Hot(player, target, hotType, duration, nil, "UNIT_SPELLCAST_SUCCEEDED", rank)
     libpredict.sender:SendHealCommMsg(hotType .. "/" .. target .. "/" .. duration .. "/" .. rank .. "/")
   end
@@ -932,39 +920,33 @@ libpredict.sender.SendResCommMsg = function(self, msg)
   -- BG groups are handled by RAID channel
 end
 
-libpredict.sender:SetScript("OnUpdate", function()
-  -- trigger delayed regrowth timers
-  local now = pfUI.uf.now or GetTime()
-  if this.regrowth_timer and now > this.regrowth_timer then
-    local target = this.regrowth_target or player
-    local duration = 20
-    local startTime = this.regrowth_start
-    local rank = this.regrowth_rank
-
-    libpredict:Hot(player, target, "Regr", duration, startTime, "OnUpdate", rank)
-    local rankStr = rank and tostring(rank) or "0"
-    libpredict.sender:SendHealCommMsg("Regr/"..target.."/"..duration.."/"..rankStr.."/")
-    
-    -- Apply next queued Regrowth if available
-    this.regrowth_target = this.regrowth_target_next
-    this.regrowth_start = this.regrowth_start_next
-    this.regrowth_rank = this.regrowth_rank_next
-    this.regrowth_target_next = nil
-    this.regrowth_start_next = nil
-    this.regrowth_rank_next = nil
-    this.regrowth_timer = nil
+-- Own casts arrive as "player". Other casters only matter as group members
+-- (the only names resolveNameFromGuid knows), so their events are filtered to
+-- the group's tokens, and solo nobody else's casts arrive at all. A member in
+-- a raid also fires as raidN for its own casts; the handler drops those by
+-- UnitIsUnit, and other repeats by castGUID.
+local GROUP_CAST_EVENTS = {
+  "UNIT_SPELLCAST_START", "UNIT_SPELLCAST_SUCCEEDED", "UNIT_SPELLCAST_INTERRUPTED",
+}
+local castunits = {}
+local function RegisterCastEvents()
+  local n, token = 0, IsInRaid() and "raid" or "party"
+  castunits[1] = "player"
+  for i = 1, IsInRaid() and GetNumRaidMembers() or GetNumPartyMembers() do
+    castunits[i + 1] = token .. i
+    n = i
   end
-end)
-
--- Own casts arrive as "player"; every other caster fires once per unit token
--- it currently holds (raidN, target, nameplateN, ...), so other-unit handlers
--- drop the repeats by castGUID.
-libpredict.sender:RegisterEvent("UNIT_SPELLCAST_SENT")
-libpredict.sender:RegisterEvent("UNIT_SPELLCAST_START")
-libpredict.sender:RegisterEvent("UNIT_SPELLCAST_DELAYED")
-libpredict.sender:RegisterEvent("UNIT_SPELLCAST_SUCCEEDED")
-libpredict.sender:RegisterEvent("UNIT_SPELLCAST_FAILED")
-libpredict.sender:RegisterEvent("UNIT_SPELLCAST_INTERRUPTED")
+  for i = table.getn(castunits), n + 2, -1 do castunits[i] = nil end
+  for i = 1, table.getn(GROUP_CAST_EVENTS) do
+    libpredict.sender:RegisterUnitEvent(GROUP_CAST_EVENTS[i], unpack(castunits))
+  end
+end
+RegisterCastEvents()
+libpredict.sender:RegisterUnitEvent("UNIT_SPELLCAST_SENT", "player")
+libpredict.sender:RegisterUnitEvent("UNIT_SPELLCAST_DELAYED", "player")
+libpredict.sender:RegisterUnitEvent("UNIT_SPELLCAST_FAILED", "player")
+libpredict.sender:RegisterEvent("PARTY_MEMBERS_CHANGED")
+libpredict.sender:RegisterEvent("RAID_ROSTER_UPDATE")
 libpredict.sender:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
 
 -- Shared cleanup helper for failed/interrupted casts
@@ -980,12 +962,6 @@ local function onCastFailed()
     s:SendResCommMsg("RESNO " .. (target or ""))
     s.resurrecting = nil
   end
-  if s.current_cast == REGROWTH then
-    s.regrowth_timer = nil
-    s.regrowth_start = nil
-    s.regrowth_target_next = nil
-    s.regrowth_start_next = nil
-  end
   s.castGUID = nil
   s.current_cast = nil
   s.current_cast_target = nil
@@ -1041,6 +1017,9 @@ libpredict.sender:SetScript("OnEvent", function()
     if arg2 == "SPELL_HEAL" then OnHeal()
     elseif arg2 == "SPELL_RESURRECT" then OnResurrect() end
     return
+  elseif event == "PARTY_MEMBERS_CHANGED" or event == "RAID_ROSTER_UPDATE" then
+    RegisterCastEvents()
+    return
   end
 
   -- UNIT_SPELLCAST_SENT: arg1=unit, arg2=target token, arg3=castGUID, arg4=spellID