Souless form and Mind over Matter causes negative mana regen

Souless form: Regenerate Mana equal to 6% of maximum Life per second
Mind over matter: 50% less Mana Recovery Rate

This Should mean if I have 200 mana regen without MoM with Mom I have 100.
In reality it somehow scales with increased mana regeneration rate and if you have low enough "increased mana regen" sources you get negative mana regen.

The tooltip show the expected number but my mana is not regenerating instead it has a degen.

Update: upon further testing it seams that the mana regen also decreases and goes to negative depending on the level of current HP.

The lower the HP the lower the mana regen to the point that about 60%hp the mana regen is negative