I answered substantively, but it appears that answer is now lost.
'Summer sale' is probably a misnomer / just a package name. (Much like spring {Easter} lasted for many months.) You are probably ok.
Note that packages rotate is various fashions, so it may be gone one day, and reappear the next or the day after.
https://plarium.com/forum/en/throne-kingdom-at-war/598_general-questions/123846_is-this-a-super-pack--mega-pack-or-special-holiday-offer/?post=628576 may be topical on this. (High water marks for packs at these levels.)
WWO said:
'Summer sale' is probably a misnomer / just a package name. (Much like spring {Easter} lasted for many months.) You are probably ok. ...
Seems I am wrong about that. I see no 'Summer SALE' now. Seems it was a sale (limited time offer), after all.
The content level amounts were not unusual, so it was not a mega or super pack. Levels and prices and packs were consistent with these periodic offerings, nothing unusual, and content levels reflected where you are in the purchase cycle. e.g. < ~150 / US$4.99
Sad that Plarium did not say here that the sale packs were indeed sales and limited time offers. Wonder how much revenue they lost as a result.