Problem :
Network traffic is slow, when you start the STP on bridge group interface on router.
Log message :
000183: .Aug 13 10:08:11.549: STP: Serial0/0/0.1 is looped back
000184: .Aug 13 14:41:53.192: STP: Serial0/0/0.1 is looped back
000185: .Aug 13 16:20:01.836: STP: Serial0/0/0.1 is looped back
000186: .Aug 13 16:39:01.308: STP: Serial0/0/0.1 is looped back
How to fix :