This is related to Auchenai/Kangor change. The previous resolve order is: First healing is converted to damage, then all damage bonus effect works. So Kangor cannot work. But now the order is: Frist all healing bonus effect works, then healing is converted to damage. So spell damage cannot work. Velen works only once, correctly.
https://www.bilibili.com/video/av52735646 (5:00 to 5:35)
This is related to Auchenai/Kangor change. The previous resolve order is: First healing is converted to damage, then all damage bonus effect works. So Kangor cannot work. But now the order is: Frist all healing bonus effect works, then healing is converted to damage. So spell damage cannot work. Velen works only once, correctly.