STS-118 Liftoff: Flashes in the Plume

We watched the video of Endeavour/STS-118 launch last night, and everything generally looked good. One thing I saw shortly after liftoff made me wonder if I was seeing things. What I saw were brief yellow flashes in the normally clear SSME exhaust plume which got me to wondering if they'ld blown out some engine tubing like what happened with Columbia on STS-93.


Right before tank separation there were also flames from close to Endeavour's nose, just at the top of the tank's onboard camera. I assumed that these were caused by the RCS engines re-orienting the stack prior to tank jettison. Any comments on these observations would be appreciated.