Based on the Reddit link I posted above it seems it might be a Sony issue. I haven't used the party chat on my PS4 since the update that the Reddit posters think broke it so can't confirm if this is a widespread issue or not. Seems a bit hit and miss if it is working OK on a different VM connection.
Is the PS4 connected via Ethernet or WiFi?
As a diagnostic test, would it be possible to put the hub in modem mode and just connect the PS4 via an Ethernet cable to see if it makes any difference. This will stop the wireless functionality of the hub for the duration of the test, so I'm not suggesting it as a solution. This would help to determine if something in the router part of the hub is the issue.
EDIT - Forgot to post a link to the help page on how to switch to modem mode: