I can reliably reproduce this situation, both the problem itself, being that pulseaudio dies, and the fact that apport does not notice.
The reason for the latter is that pulseaudio is being killed with SIGKILL(!):
recvmsg(21, {msg_name(0)=NULL, msg_iov(1)=[{"\0\0\0\30\377\377\377\377\0\0\0\0\0\0\0\0\0\0\0\0", 20}], msg_controllen=24, {cmsg_len=24, cmsg_level=SOL_SOCKET, cmsg_type=SCM_CREDENTIALS{pid=14140, uid=1000, gid=1000}}, msg_flags=0}, 0) = 20 ppoll([{fd=4, events=POLLIN}, {fd=21, events=POLLIN}, {fd=10, events=POLLIN}, {fd=7, events=POLLIN}, {fd=23, events=POLLIN}, {fd=30, events=POLLIN}, {fd=34, events=POLLIN}, {fd=33, events=POLLIN}, {fd=32, events=POLLIN}, {fd=31, events=POLLIN|POLLERR|POLLHUP}, {fd=31, events=0}, {fd=24, events=POLLIN}, {fd=27, events=POLLIN}, {fd=17, events=POLLIN}, {fd=20, events=POLLIN}, {fd=16, events=POLLIN|POLLERR|POLLHUP}, {fd=16, events=0}, {fd=15, events=POLLIN}, {fd=14, events=POLLIN}, {fd=8, events=POLLIN}], 20, NULL, NULL, 8) = 1 ([{fd=21, revents=POLLIN}]) recvmsg(21, {msg_name(0)=NULL, msg_iov(1)=[{"L\0\0\0\16L\0\0\0NL\0\0\0\1TK\336\220\203\0\3D\203", 24}], msg_controllen=24, {cmsg_len=24, cmsg_level=SOL_SOCKET, cmsg_type=SCM_CREDENTIALS{pid=14140, uid=1000, gid=1000}}, msg_flags=0}, 0) = 24 read(17, "\1\0\0\0\0\0\0\0", 8) = 8 read(17, "\1\0\0\0\0\0\0\0", 8) = 8 read(17, "\1\0\0\0\0\0\0\0", 8) = 8 read(17, "\1\0\0\0\0\0\0\0", 8) = 8 read(17, "\1\0\0\0\0\0\0\0", 8) = 8 read(17, "\1\0\0\0\0\0\0\0", 8) = 8 read(17, "\1\0\0\0\0\0\0\0", 8) = 8 read(17, "\1\0\0\0\0\0\0\0", 8) = 8 read(17, "\1\0\0\0\0\0\0\0", 8) = 8 futex(0x83d66a8, FUTEX_WAIT_PRIVATE, 0, NULL <unfinished ...> +++ killed by SIGKILL +++
I can reliably reproduce this situation, both the problem itself, being that pulseaudio dies, and the fact that apport does not notice.
The reason for the latter is that pulseaudio is being killed with SIGKILL(!):
recvmsg(21, {msg_name(0)=NULL, msg_iov( 1)=[{"\ 0\0\0\30\ 377\377\ 377\377\ 0\0\0\0\ 0\0\0\0\ 0\0\0\0" , 20}], msg_controllen=24, {cmsg_len=24, cmsg_level= SOL_SOCKET, cmsg_type= SCM_CREDENTIALS {pid=14140, uid=1000, gid=1000}}, msg_flags=0}, 0) = 20 POLLIN| POLLERR| POLLHUP} , {fd=31, events=0}, {fd=24, events=POLLIN}, {fd=27, events=POLLIN}, {fd=17, events=POLLIN}, {fd=20, events=POLLIN}, {fd=16, events= POLLIN| POLLERR| POLLHUP} , {fd=16, events=0}, {fd=15, events=POLLIN}, {fd=14, events=POLLIN}, {fd=8, events=POLLIN}], 20, NULL, NULL, 8) = 1 ([{fd=21, revents=POLLIN}]) 1)=[{"L\ 0\0\0\16L\ 0\0\0NL\ 0\0\0\1TK\ 336\220\ 203\0\3D\ 203", 24}], msg_controllen=24, {cmsg_len=24, cmsg_level= SOL_SOCKET, cmsg_type= SCM_CREDENTIALS {pid=14140, uid=1000, gid=1000}}, msg_flags=0}, 0) = 24
ppoll([{fd=4, events=POLLIN}, {fd=21, events=POLLIN}, {fd=10, events=POLLIN}, {fd=7, events=POLLIN}, {fd=23, events=POLLIN}, {fd=30, events=POLLIN}, {fd=34, events=POLLIN}, {fd=33, events=POLLIN}, {fd=32, events=POLLIN}, {fd=31, events=
recvmsg(21, {msg_name(0)=NULL, msg_iov(
read(17, "\1\0\0\0\0\0\0\0", 8) = 8
read(17, "\1\0\0\0\0\0\0\0", 8) = 8
read(17, "\1\0\0\0\0\0\0\0", 8) = 8
read(17, "\1\0\0\0\0\0\0\0", 8) = 8
read(17, "\1\0\0\0\0\0\0\0", 8) = 8
read(17, "\1\0\0\0\0\0\0\0", 8) = 8
read(17, "\1\0\0\0\0\0\0\0", 8) = 8
read(17, "\1\0\0\0\0\0\0\0", 8) = 8
read(17, "\1\0\0\0\0\0\0\0", 8) = 8
futex(0x83d66a8, FUTEX_WAIT_PRIVATE, 0, NULL <unfinished ...>
+++ killed by SIGKILL +++