Static routes don't reroute after killing cross-link of external router

Part of the topology looks like following:

s005 – r1 – 10.0.88.2
   |    \ /
   |    / \
s004 – r2
s004 and s005 are paired leaves. r1 and r2 are external routers. 10.0.88.2 is an external host which was reachable by a static route.
After killing the cross-link between s004 and r1, none of the internal host is able to reach 10.0.88.2. See onos-diags and t3 files for details.