Thank you kindly krtaylor for a patch to solve:

Linked objects won't scale together properly, only the root object scales. 
This happens with scaling both up and down or inputting numbers in the edit dialog.

1 files changed, 1 insertions, 0 deletions

diff --git a/OpenSim/Region/Environment/Scenes/Scene.cs b/OpenSim/Region/Environment/Scenes/Scene.cs
index b81b2d4..c5ed958 100644
--- a/OpenSim/Region/Environment/Scenes/Scene.cs
+++ b/OpenSim/Region/Environment/Scenes/Scene.cs
@@ -1513,6 +1513,7 @@ namespace OpenSim.Region.Environment.Scenes
             client.OnUpdatePrimGroupMouseRotation += m_innerScene.UpdatePrimRotation;
             client.OnUpdatePrimSingleRotation += m_innerScene.UpdatePrimSingleRotation;
             client.OnUpdatePrimScale += m_innerScene.UpdatePrimScale;
+            client.OnUpdatePrimGroupScale += m_innerScene.UpdatePrimGroupScale;
             client.OnUpdateExtraParams += m_innerScene.UpdateExtraParam;
             client.OnUpdatePrimShape += m_innerScene.UpdatePrimShape;
             client.OnRequestMapBlocks += RequestMapBlocks;