13 month old suddenly requesting to nurse for seconds at a time constantly

My 13 month old was basically self weaned aside from in the morning when he woke up and before bedtime (bedtime was getting shorter so figured that would go next). However the last few days he has been signing for milk and pulling at my shirt randomly through out the day. Prior to this he would never request milk, and I mean never. He only knows the sign because we used it before feedings and he has known it for months. When he requests it now he latches for a few seconds and then is on his merry way until he comes back like 20-30 minutes (sometimes less) and Does the same thing again. I don’t mind nursing for however long he wants to, but this new habit is kind of annoying.

Anyone else have experience with this? Thanks!