Hi, I just want to know if this is normal and if not, why.

About 75% of the times, when I give an order to a setler to go to a store bench I just put up, I get the response it was assigned but then looking at that setler, he/she just walks around and don't go to that stand. It may take a while before they actually do.

Shouldn't they go right away if I gave them the order to do so ?

Bethesda AI.

They're assigned, but the game will take its sweet time actually walking them there. Sometimes it works, sometimes it takes a while, sometimes you'll find everyone standing in a little cluster in the middle of camp doing nothing.