According to Bulbapedia, chance of Hidden abilities being passed down while it is being possessed by female is 80% (after BW2). But in my experience while playing Reborn, the rate is close to 20%. I found a post by Amethyst in 2013 saying that it is a known issue.
My question is what exactly is the rate of hidden abilities? Divided equally with the rest of the abilities or remain 20%?
For example, my Pokemon has 2 normal abilities, 1 hidden abilities. The rate is 40/40/20 or 33/33/33?