diff --git a/src/data/backwardsCompatibility/backwardsCompatibility.js b/src/data/backwardsCompatibility/backwardsCompatibility.js
index c7c4bc78877cab4ebffdbaecf2de0273cb9a4c2b..f48faf2a5e71884ca03987708a37fa579d90f668 100644
--- a/src/data/backwardsCompatibility/backwardsCompatibility.js
+++ b/src/data/backwardsCompatibility/backwardsCompatibility.js
@@ -1185,7 +1185,8 @@ App.Update.slaveVariables = function(node) {
 		let Slave = V.slaves[bci];
 
 		if (typeof Slave !== "object") {
-			V.slaves.deleteAt(bci), bci--;
+			V.slaves.deleteAt(bci);
+			bci--;
 			continue;
 		}
 
@@ -1276,7 +1277,8 @@ App.Update.genePoolRecords = function(node) {
 			/* first check for duplicate IDs, keep the first entry and delete the others */
 			for (let bci2 = bci + 1; bci2 < V.genePool.length; bci2++) {
 				if (V.genePool[bci2].ID === slave.ID) {
-					V.genePool.deleteAt(bci2), bci2--;
+					V.genePool.deleteAt(bci2);
+					bci2--;
 				}
 			}
 		}
@@ -1312,7 +1314,8 @@ App.Update.genePoolRecords = function(node) {
 			}
 		}
 		if (dontDeleteMe === 0) {
-			V.genePool.deleteAt(bci), bci--;
+			V.genePool.deleteAt(bci);
+			bci--;
 			continue;
 		}
 		if (typeof slave.origSkin === "undefined") {