Bob Dylan has issued an apology to fans who purchased signed copies of his new book, The Philosophy of Modern Song, that were autographed using an autopen machine rather than by the folk legend’s hand.

“I’ve been made aware that there’s some controversy about signatures on some of my recent artwork prints and on a limited-edition of Philosophy of Modern Song,” Dylan wrote in a statement posted to social media. “I’ve hand-signed each and every art print over the years, and there’s never been a problem.” He went on to explain that the decision to use autopen came when a “bad case of vertigo” combined with the pandemic made it impossible for Dylan to personally autograph the large number of books he was contractually obligated to sign.

“It takes a crew of five working in close quarters with me to help enable these signing sessions, and we could not find a safe and workable way to complete what I needed to do while the virus was raging. So, during the pandemic, it was impossible to sign anything and the vertigo didn’t help. With contractual deadlines looming, the idea of using an autopen was suggested to me, along with the assurance that this kind of thing is done ‘all the time’ in the art and literary worlds.”

Dylan called using a machine “an error in judgment” that he wants “to rectify immediately” and said he is working with the book’s publisher, Simon & Schuster to do so.

Related: Bob Dylan Museum To Open In Oklahoma Next Year

Whether or not substituting autopen signatures for hand-signed autographs “is done ‘all the time,'” fans were outraged to discover the $599 books they ordered were not autographed by hand as advertised. When buyers identified what they believed to be 17 variations of Dylan’s signature, per VarietySimon & Schuster who originally refused to issue refunds, ultimately apologized for the confusion and offered a full refund to anyone who purchased a signed copy of the book.

“To those who purchased the ‘Philosophy of Modern Song’ limited edition, we want to apologize,” the publisher wrote on Twitter. “As it turns out, the limited edition books do contain Bob’s original signature, but in a penned replica form. We are addressing this information by providing each purchaser with an immediate refund.”

Bob Dylan’s Philosophy of Modern Song offers an education in songcraft via commentary from the legendary lyricist on 66 songs by other artists. It is the first book he has published since he was awarded the Nobel Prize in Literature in 2016. Order the book here (just don’t expect it to be hand-signed).