@Dasius
Every time when customer want weapon and SHIELD, after when i will get him that he will not leave. He stuck also when time runs out dont leave also when u close and open shop.
Sell them one or the other for now, That's the easiest, stay in session, approach.
Hand them either the weapon or the shield and then dismiss them.
Or
You can save and reload when they're stuck after selling them both, but some items may need to be reassembled as a result of doing that, or become unsellable (certain things like the wood part of a shield, when not attached to anything else, become useless on reload)