Fixes for patch 12.6 from League of Legends. Which elements required additional attention from developers

What hotfixes did the developers have to release after the update 12.6 was introduced to the live servers?
Regular updates, which typically come to League of Legends every two weeks before being rolled out to live servers, are tested on the PBE. However, it is not always possible to discover the full potential of an item or hero after the changes or to test all abilities or runes for errors.
Creators often release additional fixes after the patch is released on the servers to eliminate bugs or introduce hotfixes of the implemented patches. What did the devs have to work on after the 12.6 release?
The fixes from patch 12.6
The fixes, which were introduced on the servers on March 30, fix the broken Illaoi skill and fix the new rune – Treasure Hunter.
Illaoi
- Fixed a bug where Illaoi’s W-Harsh Lesson would not deal bonus damage based on the target’s maximum health
Treasure Hunter
- Fixed a bug where champions with Treasure Hunter would get bounty stacks but no gold if the user was dead when they scored a takedown
- Fixed a bug where Treasure Hunter would grant too much gold upon getting multiple takedowns at the same time
The new rune, despite its problems, is doing quite well. According to leagueofgraphs.com, it is chosen by more than 56% of players, and nearly 50% of those games are won.
Illaoi, on the other hand, has received quite a few bug fixes as well as an ultimate update that should place tentacles more accurately. However, not everything went as it should, because bugfixes created another problem that the developers had to deal with.