diff --git a/gui/droneView.py b/gui/droneView.py
index cb08f8d1d..e506c278d 100644
--- a/gui/droneView.py
+++ b/gui/droneView.py
@@ -147,6 +147,7 @@ class DroneView(Display):
     def _merge(self, src, dst):
         sFit = Fit.getInstance()
         fitID = self.mainFrame.getActiveFit()
+
         if sFit.mergeDrones(fitID, self.drones[src], self.drones[dst]):
             wx.PostEvent(self.mainFrame, GE.FitChanged(fitID=fitID))
 
diff --git a/service/fit.py b/service/fit.py
index 719fb7b6a..2b87fefd3 100644
--- a/service/fit.py
+++ b/service/fit.py
@@ -726,8 +726,14 @@ class Fit(object):
         else:
             fit.drones.remove(d1)
 
-        d2.amount += d1.amount
-        d2.amountActive += d1.amountActive if d1.amountActive > 0 else -d2.amountActive
+        d2.amount += getattr(d1, "amount", 0)
+        d2.amountActive += getattr(d1, "amountActive", 0)
+
+        # If we have less than the total number of drones active, make them all active. Fixes #728
+        # This could be removed if we ever add an enhancement to make drone stacks partially active.
+        if d2.amount  > d2.amountActive:
+            d2.amountActive = d2.amount
+
         eos.db.commit()
         self.recalc(fit)
         return True