I'm not 100% sure if it's a bug, but at least I thought it looked a little weird.
When placing an inserter next to a wagon, two non-equal hitboxes are shown.
Obviously not game-breaking, but I would expect a single hitbox to be shown here.
See screenshot
I still see the behaviour on 0.17.6
I've attached the save to this reply.
You can see the behaviour when holding an inserter next to a wagon which also stands close to a station
Hi, this is not a bug. One box is a wagon alignment markup, showing wagon positions for a train standing in the nearby station. The other is the wagon itself.