Is there an internal cooldown on firestarter procs? (BLM)

It seems like you can get up to 2 procs per X amount of time period, and then until that time period resets you can't get anymore procs. I will constantly get 2 procs in a row and then not see any again for a good 8-12 casts. Seeing as over a long period of time 2 of every 5 should proc, it just seems coincidental that I see this pattern almost every time I play.

Often when you get double procs in a row you lose one because you can't afford to stop casting, so I'm just wondering if anyone else has noticed there to be an internal cooldown on the firestarter proc.