diff --git a/server/voxel_server.cpp b/server/voxel_server.cpp
index 38d6583b..117dfe03 100644
--- a/server/voxel_server.cpp
+++ b/server/voxel_server.cpp
@@ -817,8 +817,8 @@ static void copy_block_and_neighbors(const FixedArray<Ref<VoxelBuffer>, Cube::MO
 
 		{
 			RWLockRead read(src->get_lock());
-			for (unsigned int ci = 0; ci < channels.size(); ++ci) {
-				dst.copy_from(**src, src_min, src_max, dst_min, ci);
+			for (unsigned int ci = 0; ci < channels_count; ++ci) {
+				dst.copy_from(**src, src_min, src_max, dst_min, channels[ci]);
 			}
 		}
 	}