How to prevent a user from Finishing a Job Card without completing all the sub processes?

I have create a set of Operations. In this there is an Operation which has multiple Sub Operations.

While trying out this feature I observed that when we are working on a Job Card which has multiple Sub Operations we can Finish the Job Card by setting the Completed Quantity in the grid equal to Qty To Manufacture without completing each Sub Operations individually.

How can we prevent a user from doing this?

Another thing that I observed is probably a bug.

When we start a sub operation and stop it the user is asked to enter quantity and this entered quantity keeps on adding to the Time Log grid. After completing all sub operations when we Submit the Job Card ERPNext shows error that the Total Completed Qty is greater then Qty to Manufacture.

Actually this should not happen. After all in most cases the Completed Qty is going to be the same in all Sub Operations.