Issue with updating quantity in Side Cart

I am implementing the Cart All in One plugin for a client and we are having an issue with the side cart function. Sometimes it is not possible to use the plus and minus buttons to adjust the quantity of products. Also not possible to remove an item. But sometimes it works, so it is very unpredictable and I cannot find an obivous reason for the issue. Do you have an idea about how we can make it work reliably?