Trying to find the cause of #5729

core/src/com/unciv/logic/civilization/CivInfoStats.kt

@@ -51,7 +51,9 @@ class CivInfoStats(val civInfo: CivilizationInfo) {
         }
         // Sort by descending maintenance, then drop most expensive X units to make them free
         // If more free than units left, returns empty sequence
-        unitsToPayFor = unitsToPayFor.sortedByDescending { it.maintenance }.drop(freeUnits)
+        // There's something here that causes a bug and I'm not sure where, so let's try taking this apart piece by piece
+        unitsToPayFor = unitsToPayFor.sortedByDescending { it.maintenance }.toList().asSequence()
+        unitsToPayFor = unitsToPayFor.drop(freeUnits)
         val numberOfUnitsToPayFor = max(0.0, unitsToPayFor.sumOf { it.maintenance.toDouble() }).toFloat()
 
         val turnLimit =

core/src/com/unciv/models/ruleset/Building.kt

@@ -790,7 +790,7 @@ class Building : RulesetStatsObject(), INonPerpetualConstruction {
         return ruleset.tileImprovements[improvementUnique.params[0]]
     }
 
-    fun isSellable() = !isAnyWonder() && !uniques.contains("Unsellable")
+    fun isSellable() = !isAnyWonder() && !hasUnique(UniqueType.Unsellable)
 
     override fun getResourceRequirements(): HashMap<String, Int> {
         val resourceRequirements = HashMap<String, Int>()

core/src/com/unciv/models/ruleset/unique/UniqueType.kt

@@ -209,6 +209,9 @@ enum class UniqueType(val text:String, vararg targets: UniqueTarget, val flags:
     MustBeNextTo("Must be next to [terrainFilter]", UniqueTarget.Building),
     MustNotBeNextTo("Must not be next to [terrainFilter]", UniqueTarget.Building),
 
+    Unsellable("Unsellable", UniqueTarget.Building),
+
+
     //endregion