Advanced Book Chests

I did Canyon expert 1 through 15 the last 2 days, and I saw and luckily got an Adv skill chest. It was a Physical one though and had Kamikaze in it. But to do all 15, and then I did 3 SS experts and only 1 skill chest to show up?????

You see around 2 Chestbooks in 11 Attempts, stick with it, its normal and ok

Nothing is normal in this drop rate, should be 100%!!!!!!!!!
Because many ppl only go for this
This drop rate makes the ppl that already got the attacks invincible in the ladder & pvp

Maybe after last nights update something changed. I opened three gold chests today and got three Advance Book chests in a row. Was a haypi day for me.