Guild Wars 2

Hi, I coldn’t find in both Vale Guardian’s chest and Gorseval’s chest the Compendium of Knowledge, which should be 100% guaranteed.
Bug or what?
(Someone told me that it’s because of no more mastery to train but I’m still missing some masteries and I had one of them active the moment I opened chests, so that can’t be the reason).

AndrewMcLeod.3857:

The Compendiums of Knowledge automatically give you experience towards your active HoT mastery when you loot them from the chest. Did you not get the experience towards your masteries when you looted the chest, or were you just expecting the items to be in your inventory?

In fact both. I was expecting it to be in inventory but I didn’t see an advancement with mastery bar neither but maybe I’m wrong and didn’t remember correctly, I’ll check this again next time