Clean up

forge-game/src/main/java/forge/game/cost/CostPartMana.java

@@ -155,6 +155,8 @@ public class CostPartMana extends CostPart {
 
     @Override
     public boolean payAsDecided(Player payer, PaymentDecision pd, SpellAbility sa) {
+        sa.clearManaPaid();
+
         // decision not used here, the whole payment is interactive!
         return payer.getController().payManaCost(this, sa, null, cardMatrix, true);
     }

forge-gui/src/main/java/forge/player/HumanPlaySpellAbility.java

@@ -144,6 +144,7 @@ public class HumanPlaySpellAbility {
             }
         }
 
+        // reset is also done early here, because if an ability is canceled from targeting it might otherwise lead to refunding mana from earlier cast
         ability.clearManaPaid();
 
         // This line makes use of short-circuit evaluation of boolean values, that is each subsequent argument