diff --git a/core/src/com/unciv/logic/automation/UnitAutomation.kt b/core/src/com/unciv/logic/automation/UnitAutomation.kt
index da57e2cff0..d698e8eef7 100644
--- a/core/src/com/unciv/logic/automation/UnitAutomation.kt
+++ b/core/src/com/unciv/logic/automation/UnitAutomation.kt
@@ -73,11 +73,9 @@ object UnitAutomation {
     }
 
     internal fun tryUpgradeUnit(unit: MapUnit): Boolean {
-        val upgradesTo = unit.baseUnit().upgradesTo
-        if (upgradesTo == null) return false
-
-        val upgradedUnit = unit.civInfo.gameInfo.ruleSet.units.getValue(upgradesTo)
-        if (!upgradedUnit.isBuildable(unit.civInfo)) return false
+        if (unit.baseUnit.upgradesTo == null) return false
+        val upgradedUnit = unit.getUnitToUpgradeTo()
+        if (!upgradedUnit.isBuildable(unit.civInfo)) return false // for resource reasons, usually
 
         val upgradeAction = UnitActions.getUpgradeAction(unit)
         if (upgradeAction == null) return false