I also have problems with the gift shops. I solved them not entering the shop when I found out they need an entire 4 meter square open area to enter - cannot pass glass/items the way guests normally do (I suspect they've made the gift shop process similar to the way keepers transition from guest abilities (passing through most objects) to animal abilties (not able to pass through most objects).
However, whenever I open my zoo, some guests are always 'trapped' (ie: doing the trapped animations and sounds) on the shop floor. They've not fallen off and no changes are made to the shop (and new guests can walk about normally). I was usually able to simply pick them up and move them to either another part of the shop or outside to a path ... until today. Now, when I pick them up, whenever I 'drop' them they reappear at their original trapped location (still trapped).
I think the team needs to iron out some more bugs with the shops.