diff --git a/node_modules/fractional-indexing/src/index.js b/node_modules/fractional-indexing/src/index.js
index 0c26359..027e483 100644
--- a/node_modules/fractional-indexing/src/index.js
+++ b/node_modules/fractional-indexing/src/index.js
@@ -19,7 +19,8 @@ export const BASE_62_DIGITS =
 function midpoint(a, b, digits) {
   const zero = digits[0];
   if (b != null && a >= b) {
-    throw new Error(a + " >= " + b);
+    // Duplicate keys: return key after a (avoids "c1NY >= c1NY" from y-excalidraw)
+    return a + digits[1];
   }
   if (a.slice(-1) === zero || (b && b.slice(-1) === zero)) {
     throw new Error("trailing zero");
@@ -213,7 +214,7 @@ export function generateKeyBetween(a, b, digits = BASE_62_DIGITS) {
     validateOrderKey(b, digits);
   }
   if (a != null && b != null && a >= b) {
-    throw new Error(a + " >= " + b);
+    return generateKeyBetween(a, null, digits);
   }
   if (a == null) {
     if (b == null) {
