TCP/IP and General Networking: when using multiple default gateways and static/RIP routing, if interface is down, then SG switches over to RIP/static route but when the interface is back up it doesn't switch back to the interface route.
This will be fixed in SGOS 5.5.4.1 GA, currently (October 8, 2010) due out in November, 2010. Check the release notes for bug# 142638.
The fix will also be in SGOS 5.4.5.1 GA, currently due out in mid-October, 2010. Check the release notes for b#126775.