Certain cyberzombies will be periodically immune to all forms of damage and emit some particle effects, I am unsure if this is an intentional feature from one of the parts, and if so, would it be possible to disable it in the config?

No update for 2+ months, assuming fixed

That is most definitely a feature, as a threat detection augment is causing this, which allows dodging some attacks if wearing light armor or no armor (light armor being anything of leather level protection). No way to disable it that I can see, sorry.

Only entity based damaged have 65% chance of being absorbed. There other means to damage entities than direct it...