Device: iPhone 7

iOS: 13.5

1. Foli's passive Living Armor [P] Level 3 ability states, "Heals this Champion by 20% of their MAX HP and boosts the Turn Meter by 50% whenever an enemy places a [Stun], [Freeze], [Sleep], or [Provoke] on this Champion.  Immediately removes all  [Stun], [Freeze], [Sleep], and [Provoke] debuffs from this Champion."  None of these effects take place when Foli is stunned, frozen, slept, or provoked in the arena by an enemy champion.  In arena, Foli incurs the full effect of any and all of these debuffs without experiencing any or all benefits from his passive. 

WTR:

Use Foli in arena against a [Stun], [Freeze], [Sleep], or [Provoke] champion

An enemy champion places a [Stun], [Freeze], [Sleep], or [Provoke] debuff on Foli

Foli experiences the full effect of each of these debuffs without activating any passive abilities from his Living Armor [P] Level 3 ability.

2. When I placed Foli in the lead in Clan Boss, he seems to "immediately remove" the stun but did not seem to experience the "heals this Champion by 20% of their MAX HP and boosts the Turn Meter by 50%" part of the passive ability.

WTR

Use Foli in the lead of a Clan Boss team.  I tested Foli on Clan Boss Hard.  

Run the battle and Foli seems to remove [Stun] from the Clan Boss but does not seem to experience the "heals this Champion by 20% of their MAX HP and boosts the Turn Meter by 50%" part of the passive ability.  Other champions were stunned in the Clan Boss runs that were tested.  

3. Tests in other content were not performed but that's not to say some of the same issues would still be experienced in other content.

For an illustration of the issue, see Hell Hades' YouTube video posted on April 25 entitled, "RAID: Shadow Legends | PLATINUM ARENA, FOLI IS TOP TIER! LIVE FROM STREAM!" at minutes 20:37 and 22:10.  Link is included below:

https://www.youtube.com/watch?v=kVz_3xP-Pe0

Hopefully it's an easy fix.  Look forward to a solution.