This has happened to me as well lots of times, but they always pick up again after a while and finish.

Just be patient. It has sometimes taken up to two and a half hours before download has been completed.

It happens both with 4.9.37Pro, 4.10.3 and 4.10.5

BTW upgraded to 4.10.9Pro yesterday. And it has been all good. A real Improvement from 4.9.37Pro