Weird healing tempo & Ivy watcher's covenant interaction

[dancedanceincineration]

Watcher's covenant's lifesteal isn't innate, so I'd reckon it should trigger healing tempo, but it doesn't.
Video shows this.

 

[nolan_exe]

Similar thing with Infernus' Napalm tier 2. Seems like tempo isn't distinguishing from innate lifesteal of abilities vs lifesteal from items.