diff --git a/LiteCore/Database/CollectionImpl.hh b/LiteCore/Database/CollectionImpl.hh
index 39d8b018a..0a61db54c 100644
--- a/LiteCore/Database/CollectionImpl.hh
+++ b/LiteCore/Database/CollectionImpl.hh
@@ -454,6 +454,7 @@ namespace litecore {
                         vecOpt.minTrainingCount = c4Opt.minTrainingSize;
                         vecOpt.maxTrainingCount = c4Opt.maxTrainingSize;
                         vecOpt.probeCount       = c4Opt.numProbes;
+                        vecOpt.lazy             = c4Opt.lazy;
                         vecOpt.validate();
                     } else {
                         error::_throw(error::InvalidParameter, "Vector index requires options");