diff --git a/src/libexpr/primops/fetchTree.cc b/src/libexpr/primops/fetchTree.cc
index ad76af5b5..b49bd02e7 100644
--- a/src/libexpr/primops/fetchTree.cc
+++ b/src/libexpr/primops/fetchTree.cc
@@ -199,8 +199,8 @@ static void fetchTree(
     if (state.settings.pureEval && !input.isLocked()) {
         if (input.getNarHash())
             warn(
-                "Input '%s' is unlocked (e.g. lacks a Git revision) but does have a NAR hash. "
-                "This is deprecated since such inputs are verifiable but may not be reproducible.",
+                "Input '%s' is unlocked (e.g. lacks a Git revision) but is checked by NAR hash. "
+                "This is not reproducible and will break after garbage collection or when shared.",
                 input.to_string());
         else
             state
diff --git a/src/libflake/lockfile.cc b/src/libflake/lockfile.cc
index d3dac19c5..d0d339f9f 100644
--- a/src/libflake/lockfile.cc
+++ b/src/libflake/lockfile.cc
@@ -77,8 +77,8 @@ LockedNode::LockedNode(const fetchers::Settings & fetchSettings, const nlohmann:
     if (!lockedRef.input.isLocked() && !lockedRef.input.isRelative()) {
         if (lockedRef.input.getNarHash())
             warn(
-                "Lock file entry '%s' is unlocked (e.g. lacks a Git revision) but does have a NAR hash. "
-                "This is deprecated since such inputs are verifiable but may not be reproducible.",
+                "Lock file entry '%s' is unlocked (e.g. lacks a Git revision) but is checked by NAR hash. "
+                "This is not reproducible and will break after garbage collection or when shared.",
                 lockedRef.to_string());
         else
             throw Error(