For the past couple years, Google has been trying to communicate that 301 and 302 redirects pass full PageRank. They documented how redirects work in Google, they mocked those that argued, called SEOs out as being wrong but yet, still today, SEOs don't believe Google when they say that 301 and 302 redirects pass full PageRank.
Just the other day, Christoph Cemper from Link Research Tools said "302 pass rankings in a durable way. 301 erodes them over time," based on a study he ran a year or so ago. In which Gary Illyes from Google responded "What... How on earth did you come to that conclusion?! O.o."
What... How on earth did you come to that conclusion?! O.o
— Gary "鯨理" Illyes (@methode) September 18, 2017
A few days before, Gary also said this:
There virtually no way you can test this externally. We have hundreds other signals besides PageRank and you would likely measure those
— Gary "鯨理" Illyes (@methode) September 15, 2017
I said that cos people were obsessing about PageRank specifically in the context of redirs. We tested it then we told you the results /shrug
— Gary "鯨理" Illyes (@methode) September 15, 2017
Google specifically looked into it and told SEOs they pass full PageRank but some SEOs tested it and said no, Google does not. Google says that SEOs cannot fully test this as their are too many reasons for ranking changes.
A lot of the confusion might come from back in 2010 Matt Cutts saying redirects do dilute PageRank. But times change.
Who do you believe?
Forum discussion at Twitter.