Learning rate

PM Revision Mock Exam

A company predicted that the learning rate for production of a product would be 70%. The actual learning rate turned out to be 75%. The following possible reasons were stated for this:

i) The number of new employees recruited was higher than expected
ii) Unexpected problems were encountered in production

Which of the above reasons could have caused the difference between the expected rate and the actual rate of learning?

Answer- Both of the above

My question is how can unexpected problems encountered in production lead to a higher learning rate? For me, the actual learning rate which is 75% is higher and I would expect that problems encountered in production would have decreased the learning rate.