Guild Wars 2

I did the bounching mushroom track to learn it.
I have now 1 full bar on itzel lore, but i cant learn the mushrooms mastery. how can i learn it if there is nothing clickable there?

and shows it needs another point, but 1 cost 1 bar i think?
(see pic)

Not a bug.

You have 0 Mastery Points, the large 1 is displaying how many mastery points you have spent.

One is Mastery Rank; you have achieved Level 1 there.

The other is Mastery Points; you have 0 in stock. You need only interact with a Mastery Point area, or obtain one through an achievement.

Good luck.