diff --git a/changelog.in b/changelog.in
index 27918d6c45..ea427f5f2d 100755
--- a/changelog.in
+++ b/changelog.in
@@ -69,6 +69,14 @@ Date: 2020-??-??
 [DESCRIPTION]
 Let's see.
 
+[ENTRY]
+Module: flatzinc
+What:   bug
+Issue:  171
+Rank:   minor
+[DESCRIPTION]
+Correctly unshare variables for inverse constraint.
+
 [ENTRY]
 Module: flatzinc
 What:   bug
diff --git a/gecode/flatzinc/registry.cpp b/gecode/flatzinc/registry.cpp
index 2b96a76429..e8db027039 100755
--- a/gecode/flatzinc/registry.cpp
+++ b/gecode/flatzinc/registry.cpp
@@ -1220,12 +1220,12 @@ namespace Gecode { namespace FlatZinc {
     void
     p_inverse_offsets(FlatZincSpace& s, const ConExpr& ce, AST::Node* ann) {
       IntVarArgs x = s.arg2intvarargs(ce[0]);
-      unshare(s, x);
       int xoff = ce[1]->getInt();
       IntVarArgs y = s.arg2intvarargs(ce[2]);
-      unshare(s, y);
       int yoff = ce[3]->getInt();
-      channel(s, x, xoff, y, yoff, s.ann2ipl(ann));
+      IntVarArgs xy = x + y;
+      unshare(s, xy);
+      channel(s, xy.slice(0, 1, x.size()), xoff, xy.slice(x.size()), yoff, s.ann2ipl(ann));
     }
 
     void