Every Bible translation has some bias based on the doctrinal belief of the translators. Since there are multiple ways to translate certain passages, there is a requirement for interpretation as part of translation. This is also the case with the NWT. This is way an argument over how to translate a passage such as John 1:1 can be irreconcilable.
The older NWT was less biased than the new NWT, as it highlighted via [ .. ] where the translators had added a word to make sense of a passage. The NNWT does not do this, and so quite blatantly has made a translation to fit the doctrinal views of Watchtower without the reader realising that passages do not read as generally considered acceptable.