--- a/net/minecraft/advancements/AdvancementManager.java
+++ b/net/minecraft/advancements/AdvancementManager.java
@@ -36,6 +36,10 @@
          try {
             JsonObject jsonobject = JSONUtils.func_151210_l(p_240923_3_, "advancement");
             Advancement.Builder advancement$builder = Advancement.Builder.func_241043_a_(jsonobject, new ConditionArrayParser(p_240923_2_, this.field_240922_d_));
+            if (advancement$builder == null) {
+                field_192782_a.debug("Skipping loading advancement {} as it's conditions were not met", p_240923_2_);
+                return;
+            }
             map.put(p_240923_2_, advancement$builder);
          } catch (IllegalArgumentException | JsonParseException jsonparseexception) {
             field_192782_a.error("Parsing error loading custom advancement {}: {}", p_240923_2_, jsonparseexception.getMessage());
