Hello,
This is common fault being seen currently with the RB3011.
Mikrotik support say that it should be fixed in the next few days and then in next routerOS.
The problem comes from from using a software bridge to bind interfaces together, if you set them up slave to another interface then there are no errors. The downside to this is to make all ports switch you have to put a patch cable between switch chips!
I am currently waiting for the fix as I need to add in SFP to bridge.
http://forum.mikrotik.com/t/weird-routing-loop-in-logs-but-there-isnt-one/95280/1