Interesting tidbit. This comes from J.E "Rik" Alvarez at TFcon 2018 back in October, former creative manager (and ongoing independent contractor?) at Hasbro who worked on Transformers Prime and apparently every live action Transformers movie except the first. In response to being asked about the future of the Bay series post-TLK, he stated that Bumblebee started off as a prequel, however he thought it was actually turning into a reboot in a new timeline. The main bump in the road being potential WW2 scenes directly referencing The Last Knight that we'd have to ignore. ...scenes that never actually made it into the finished movie, along with the laundry list of other changes we already know were made that cut ties with Bay's timeline. Interesting to hear it from someone associated with Hasbro before the movie had even released. 9 minutes in.