IBS Prologue, completing story steps gives no XP?

[Speechless.3647]

Hello,

I started IBS prologue yesterday, did the first story step (Coming home), unlocked IBS Masteries and started with the Raven one.

 

Killing mobs, completing events etc. all fill up my mastery XP bar but when I complete a story step (did Revels & Rivals and Bad Blood already) even though it briefly shows the XP number on my screen my mastery XP bar doesn't move an inch. It's like I am getting the XP but it's wasted? Tried changing mastery track but with the same results.

 

So I was wondering if it's a bug because completing story steps gives significant XP and it's a shame losing it...