Since the 1.16 stable update, the down button on the PlayStation D-pad also activates VoIP while in menu screen or the inventory.
When in Menu or Inventory, while navigating with the arrow buttons on the PlayStation 5 Dual Sense Controller, the down button activates the VoIP function.
Especially when navigating through menus fast (double push), this can activate the always on VoIP function.
Under version 1.15, VoIP could not be activated via the down button while in menu screen or inventory.