Executor Tier 4 “Galactic Challenge Tickets”

Today, on the 15th, I just promoted my Executor to 7 stars via the bonus tier in “Events.” Being a perfectionist, I wanted to go back into the Journey Guide tiers under Discarded Doctrine and get successful 3 stars completions to make the tier “description” appear neat. I was able to get 3 star completions on tiers 1, 2, and 3, before taking a break and then returning to hit tier 4 later. However, immediately after attempting tier 4 and successfully dominating the enemy with no deaths on my fleet, I received the error: INSUFFICIENT CURRENCY: You do not have enough Galactic Challenge Tickets to attempt this Battle.” After receiving this, I re-completed the same mission over and over again successfully, only to receive the same result every time. I am currently unsure of what to do, or if I will just need to wait until next month to complete it when the event rolls around. If anyone has any solution, I would greatly appreciate it!