The baby is sleeping on its stomach, which is a suspected cause of crib death.
An 11 month old infant is capable of rolling over on their own. “Back to Sleep” is for infants too young to roll over on their own.
Both of my sons slept on their stomach. It was advised back then so that if they threw up, they wouldn't aspirate the vomit. The oldest son is 56. The youngest 51, so it didn't kill them, but the Covid shots the dummies both got just might.