Hi! This is correct. It seems the specific event is coded in a way where if you bought purification runes before packs appeared again, the system will think that you already bought 5 packs.

We deeply apologize for this situation and we have already brought this up to the team. Due to this reason, we will be bringing back the pack again in the future with similar price, which will give a chance to players that were not able to claim packs this time to obtain them in the future.

Sorry again and thank you so much for your understanding. Please feel free to contact us if you have any questions.

~Jib