Oh gosh, we used to have a neighbour like your child (same age). Lovely family, sensible, caring etc- but the kid was constantly at ours, knocking on the door for my kid, sat on the wall singing when we were eating to attract my kid's attention...
As soon as we arrived back from a day out, neighbour kid would be on our doorstep.
It was relentless and bordered on harrassement, tbh. I mean my kid was happy to play but not All The Time.
Parent was apologetic but did not really stop it.
Turns out the kid did have some mild LD, but yeah, it was quite exhausting tbh.
I would say we have lived next door to quite a few kids, but this was the only one who behaved like this, so yes, I would say it is not usual.