Three times in the past week I've been killed by a mob of enemy players that were not visible until it was too late. Latest episode was last night in Cyrodiil. While at Bruma, I saw Bleakers was flagged so I mounted up and headed to the outpost. Level 60 mount with rapids, so I was moving at a pretty good clip.
Arrived at Bleakers front door, and there were 2-3 NPC guards and no players. Looking for the flagged wall, I dismounted and ran towards the northern Postern door. I'd been near the outpost for at least 3-4 seconds at this point. Just as I approached the steps, about 20 enemy players appeared both behind and in front of me. In less than a second I was killed. This is on PS4. Other players have also mentioned in zone chat that they are seeing similar delays before enemy players will appear on their screen when porting in or riding in quickly to a keep where a battle is taking place. I'll be happy to try and get one of these events on video if needed.
PS4NA