When does a post-retirement payout from employer require a W2 instead of 1099-MISC?

The 1099-MISC from my old employer (I retired in 2018) was for a lump-sum payout from an investment fund used to pay employees who stay with the company more than 10 years. TurboTax wants to classify this as wages requiring a W2. And/Or require me to file a form SS-8.