Is this a toddler self-weaning?

AmyRI

DS has been nursing in the morning and at night for a little over a month now. He always always always wants to nurse in the morning, and takes a full feeding. But lately, during the bedtime feeding, he's only been half interested. He asks to nurse, but then sucks 3 or 4 times and pops off and starts smiling and talking or looking around the room. He'll do that a couple more times, swallowing maybe once or twice (definitely not on there long enough to trigger a let-down, so he's not getting much) and then ask to switch sides. Switch, do the same thing, and then he's back to playing or reading books.

I figured he would just stop asking to nurse completely if he was weaning.... did anyone else's toddler wean by shortening the session like this?

Thanks!