I have just been fixing 184.108.40.206 with the formkey code into my Theme's billing and shipping code pages. That has mostly restored the functionality with respect to those with Form Key security turned on.
However, the Update Quantity functionality is broken. Entering a new Qty fails to change it to the new value. This is on the main Cart page
The Update Qty feature on the Basket Pull down (top right), does work properly.
Hope you can help.