Telel was half expecting something like the exploit certain 'top' guilds like Dracarys were caught using a couple of years back. The one involving multiple attacks hitting simulatenously, and getting the stealth bonus, due to a desync exploit.
A large number of DC players have been using short timed macros to cause lag, and a back up of skills that all fire at once when the server catches up, for a very long time. ZOS never really does anything about it. The timer between skills should work but when a backlog of commands happens, a server will skip the timer to catch up.
If anyone is curious about that older desync exploit, and the people who relied on it, just go to the twitch channel this one will link below.
Once there look for highlights marked as "Super 'skilled' sorce gameplay". They're from a bit over two years ago from when there was a known issue with Vampire and stealth.
Sadly if this one was to post them directly some angry soul would get it mass reported under 'naming and shaming'. Which would also get this thread shut down.
Plus it does seem to be a different issue from what the OP seems to be having. Plus ZOS supposedly fixed at the same time they fixed the stuck in combat bug.