The bug seems to be in the game for a while now but players are ignoring it
When it comes to increasing the sustainability of some champions, Spirit Visage is an essential item for them because it increases all healing effectiveness to a great threshold. Even in season 12, Riot displayed the amount of HP recovered from this item to help players evaluate the efficacy of the item.
However, recently, a League player has discovered that The Spirit Visage has been bugged for months when it does not increase its healing from Omnivamp. This was posted on the official League of Legends subreddit forum.
Spirit Visage bug doesn’t increase healing from Omnivamp
It is worth noting that through his experiments, it is determined that the capability to increase healing is not bugged since the Revitalize points that offers the same effect as Spirit Visage still function correctly. So, the problem can only lie in the item itself.
The display of Spirit Visage does not indicate that this item improves healing from the Omnivamp
Meanwhile, despite having the same effect, Revitalize works normally
Essentially, this issue causes Fighters who rely on Omnivamp to significantly worsen in the game. While the stat of total healing effectiveness increases by only 25%, it might be the reason to turn the situation all around.
Apparently, this bug has been in the game ever since patch 11.23, according to the author of the post, and players also stated that this issue has been brought a couple of times now but most of them keep ignoring it.
Furthermore, it would be absurd for a Legendary item to increase only raw stats, rather than the healing effect. Riot Games should be able to address this problem as soon as possible. Magic resistance items in season 12 were not favored much so far and it would be unfortunate if one of the widely used item on fighters and tanks got a bug.