Guild Wars 2

I received the item ‘Invisible Mushroom Spore’ from the 1st east pylon event in Auric Basin and it has counted towards the ‘Wild Abandon’ collection but not the ’Glint’s Bastion’ collection as shown in the screenshots.

There’s 9 different spores, all with the same name and tooltip, 1 for each collection. Not a bug, intentionally designed this way.
@Affinity, it is random drop until your unlocked collections fill out, then it stops dropping.

This isn’t a bug. The Invisible Mushroom Spore is a required item for each elite specialization’s weapon collection, and as such, it will unlock the collections in alphabetical order based on the name of the elite specialization:
Berserker
Chronomancer
Daredevil
Dragonhunter
Druid
Herald
Reaper
Scrapper
Tempest
So, for example, if you wanted to unlock the Spore for your Herald’s weapon collection, you would have to kill 6 Treasure Mushrooms to unlock it for your shield collection.