Questions about Fast Metabolism ，hope the staff will reply

The PoE1 wiki contains the following description.In the case of instant life leech effects, such as Bloodseeker or legacy versions of Atziri's Acuity, the leech will end immediately regardless of whether you are at full life or not, as Brutal Fervour does not preserve or store such effects.
In PoE2, Fast Metabolism has the same effect as Brutal Fervour.
However, Fast Metabolism now allows Lech to continue existing as life recovery after its life is full.
Therefore, the combination of Soul Tether, Fast Metabolism, and Atziri's Acuity will now grant a significant amount of life and energy shield regeneration.
I'd like to know if there are any bugs in the functionality of Fast Metabolism and Leech is instant.