Lately I was thinking that my ISP is responsible to all the game disconnections since the pathping and tracert have pointed this out.
But now it seems that the issue is at ZOS server side and not mine nor the ISP.
It gotten worse since patch v2.3.11 and it needs to be fixed.
Cyrodiil is now unplayable, 999+ lag all the time.
I suspect that the code of this fix is to blame:
"Cleanse (Purge morph): Fixed an issue where this morph was not healing every group member who had a negative effect cleansed from them."
Now if any group in the game, be it a zerg or a small group in both pvp and pve is being cleansed and the code isn't implemented in a way it can't interupt the service due to too many IDs calculations, no wonder so many people get disconnected.