Continuity mistake: When Charlie is looking through her box of tapes, it shows the columns and there is nothing by Rick Astley. But from a different angle she picks a tape from the bottom of the middle column which we just saw, and it plays a Rick Astley song.
Bumblebee (2018)
1 continuity mistake
Directed by: Travis Knight
Starring: Angela Bassett, Hailee Steinfeld, Justin Theroux, Pamela Adlon
Factual error: Rob Base and DJ E-Z Rock's "It Takes Two" was not released until 1988. This movie takes place in 1987.
Memo: You kissed me!
Charlie Watson: On the cheek.
Memo: Still counts. Still counts.
Trivia: Star Hailee Steinfeld wasn't born until 9 years after the film is set. She actually had to be given lessons on things like 80's lingo and how to properly use a Walkman.
Question: Why didn't Frank Welker reprise his role as the voice of Soundwave for this film?
Answer: I couldn't find any other information, but honestly... Soundwave is barely in the movie. Probably just wasn't worth it for the production to pay Welker to come in just to record a few throwaway lines.
TedStixon
I considered that possibility as well, but since Peter Cullen reprised his role as the voice of Optimus Prime yet again for this film despite Prime's minimal involvement, it doesn't quite wash. Also, given Frank Welker's highly prolific voice acting career, it's unlikely he would have declined on the basis of pay or importance of his involvement.
zendaddy621
Soundwave was barely in the movie (he's literally only in a few shots) and only had one or two lines. As the other answer suggested, it probably just wasn't worth it for the studio to pay Welker to come in, or they just didn't feel it was necessary given that Soundwave was essentially just a blink-and-you'll-miss-it cameo. Optimus has a much larger presence, and Peter Cullen's voice is pretty synonymous with the character in the film series. Hence, it was worth it to have him return.
TedStixon