Enabled audio in and out, the bug seems to be gone from version 5.2.20.

vm-setup

@@ -179,8 +179,8 @@ if [[ ${CREATE_VM} == 1 ]]; then
         --clipboard bidirectional --draganddrop bidirectional \
         --audio ${AUDIO_DRIVER} --audiocontroller ${AUDIO_CONTROLLER} \
         --description "${DESCRIPTION}" \
-        --audioin off --audioout off 
-        # not working, bug in VB version >= 5.2
+        --audioin on --audioout on 
+        # working on VB version >= 5.2.20
     
     # set storage type to "normal" to allow update, otherwise "immutable"
     if [[ ${UPDATE} == 1 ]]; then