Pokerus is only beneficial, it would not be the cause.
To see more information on pokerus see here
To activate Primal Reversion you must have the appropriate orb (red on groudon, blue on kyogre) and it will activate upon being sent out in battle. It will loose the effect afterwoods. If this does not solve it, blame it on glitches :D
EDIT: Red and blue orbs or primal reversion does not exist in x or y only in omega ruby and alpha saphire.