I have noticed recently that certain members have a large number of reviews with favourable feedbacl (look at Better Call Saul for example). Their reviews are largely voted as helpful & everybody elses are as low as zero to 30% at best. Seems very dodgy if you check this persons other reviews.
This is an ongoing problem which IMDB are not interested in fixing, and are even internally rigging the data. (Look at the IMDB staff votes on Ghostbusters for example).
Look at the ratings for TV episodes the night before they are even screened and you will find a huge binge of 9 & 10 votes. Big Bang Theory is so ridiculous that episodes often carry an average of 9.9 with 50+ votes the night before it even gets shown.