Maud passive skill description clearly describes that it will place a Continuous Heal buffon the ally with the lowest HP at the end of her turn. In the video linked bellow Maud is the highest HP champion in the team and Titus has the lowest HP in the team. Titus has half the HP of Maud, and still Maud places the buffs on herself instead of TItus as visible in the video linked bellow. 

i

Nickname: Fara_UTD

YouTube video with the bug: click here 

Plarium ID: um5099182 | 5028248

Platform: Windows PC and Android Redmi Note 14