M&A Model: Deferred Revenue Write Down

While studying basic technical questions for M&A Model, I came across the following that I’m having trouble understanding. Hoping someone more experienced can help me out!

“Q: Is there anything else “intangible” besides Goodwill & Other Intangibles that could also impact the combined company?

A: You could also have a deferred revenue write-off. [Deferred revenue write-off] refers to cases where the seller has collected cash for a service but not yet recorded it as revenue, and the buyer must write-down the value of the Deferred Revenue to avoid “double-counting” revenue.”

Please correct me if I’m wrong, but wouldn’t the buyer simply keep the deferred revenue on their books until they perform/deliver the service/good, at which point it would appear as ‘normal’ revenue? Understanding that this is from a very elementary definition of deferred revenue, I’m guessing I’m missing something. Where does the issue of “double-counting” appear?

Would appreciate the help!