From what I’ve read in the forum, there must be a difference in language translations. Here is the text directly from the game in English:
1st Limited Pack: 50%
2nd Limited Pack: 60%
3rd Limited Pack: 1 Legendary Guaranteed
4th Limited Pack and Beyond: 50%
6th Limited Pack: Pengbot (Legendary) Guaranteed
Every 6th Limited Pack thereafter: 1 Limited Time Only Legendary Guaranteed except Pengbot. (For example: 12th, 18th, 24th…etc.)
(Notice the parts I highlighted. There’s no promise of a Legendary every three packs. Only every 6th.)
Regardless of what your text says, you CAN roll three packs without a legend. I have, unfortunately, done it myself after Pengbot.
See also this reply in another thread: