No. The RNG is not broke. Your RNG isn't a set number it is a COMPLETELY random number.
You first encounter a shiny after 10 encounters but then next time you encounter a shiny (if you are lucky enough) you encounter it after 213685 encounters. Then the next time you encounter a shiny it could be after 1 encounter.
Ok that is enough.
No, your RNG isn't broken, you just seem to be very unlucky with your Shiny encounter rate is going up.