I was recently victorious in a prime championship (adaptive Archon) but there were 14 players in attendance I know we do not get the Aember shards for the event but is my Worlds invite still valid or do I need to find another prime to go to?

I don't think the invite is valid. You may need to go to another prime.

I would suggest contacting keyforge by email. They rarely post on this forum, and confirming the validity of a tournament is not something a random user can do. They are expecting a certain number of prime championships to take place, so if one is missing, then they will most likely want it to be fixed.

On 11/30/2019 at 4:27 PM, Highzander said:

I was recently victorious in a prime championship (adaptive Archon) but there were 14 players in attendance I know we do not get the Aember shards for the event but is my Worlds invite still valid or do I need to find another prime to go to?

Win is valid, as long as the store submitted it following the instructions included in the prize kit. Aembershards were the only thing that depended on the 16 player minimum.