Bug Report:Conflict of life loss from Soul Tether and kind of life recover

I build a CI Titan with Soul Tether
for which ,I 've only 1 hp,Soul Tether's effect is loss 5% maxlife per second.
without other help,I'll die in 20s,even if my hp still display as 1 during it.
It's ok

but when i take a life regeneration equip,like 3.5 per second,I'll never die from it,It's OK as well

Then I try replace life regeneration to Time of Need,which heal 500 hp per 0.5s
I died...

Why?Is this a BUG?
Fix it plz!