I have had this problem multiple times now and so has my friend with whom I'm playing on the PS4.
We have our own league, set on private and full qualifying. We experience no problem in Q1, but in Q2 I suddenly hear nothing but some bird sounds. This makes it impossible to get to a competitive lap time.
We have seen this problem now 4 times in 9 races, in two different leagues.
Anybody else have experienced this really annoying bug?