Are you using switch groups? This is a known issue, see http://forum.mikrotik.com/t/weird-routing-loop-in-logs-but-there-isnt-one/95280/1 seems to be fixed in ROS 6.35rc37
Check Switch > switch1 is Switch all ports ticked?
Are you using switch groups? This is a known issue, see http://forum.mikrotik.com/t/weird-routing-loop-in-logs-but-there-isnt-one/95280/1 seems to be fixed in ROS 6.35rc37
Check Switch > switch1 is Switch all ports ticked?