I have the Mikrotik C52iG with 7.16.1.
When using IPv6, if you want to see the connections you must use the CLI as the GUI is showing 0 items.
CLI:
GUI:
Seems to be webfig-only related, as Winbox shows v6 connections correctly for me
You are correct. This does work in Winbox.
So this is just a bug in the web portal.