Thank you for your response. Please note I sent private replies to Tu Tran, not sure you have seen those?
We are now in the process of migrating our existing dev site (running theme version 2) to a new dev site (running theme version 3).
We have confirmed version 3 does not add to cart if quantity requested is more than stock available.
So you can mark this issue as resolved.
- Official hour: Mon-Fri / 9am-5pm
- Location time: GMT + 7