Hi! My LO is 12 weeks. He is shooting through language skills (he started blowing raspberries and does not stop babbling at us/toys!), however we are still very much in trenches in terms of tummy time. When sat on the knee, he controls his head well enough (I think), but he simply does not engage in tummy time. He will lay down like a potato with no interest in lifting/moving his head. Occasionally will scream his head off or fall asleep. No amount of sound or toys enticing works, he just shuts off.
Does it mean potential issues? Delay?