only ever noticed mine doing it once...dark road, no one behind me, lit up the whole road behind....could see that without lookin' in mirrors etc.
Mine tends to pop blue flames rather than long lasting ones like yours pablo..... does that quite frequently too....
On other thing i've noticed, when mine pops, it sounds like it's popping drivers side rear...which is weird, cause the exhaust doesn't ever venture to that side of the car! LOL