I have tried playing the main quest line a little bit and found a few issues whilst doing so,
I am playing on a Macbook Pro, so not necessarily the optimal gaming platform, but for the previous chapters I have played, I don't recall having these problems.
On the first battle with a large called winged creature, I found when I went in to attack, suddenly the whole screen went black until the battle was over and then when it refreshed I was left wearing all the text from the UI ... had to quit and relog to fix, as I couldn't even get into the games menus to logout ...

I have also experienced two random crashes of the game, just as things were getting good ... again something that hasn't occurred while playing on the normal ESO server.
First crash after talking to the Blue dragon after the delve, and the second occurred just on entry to the house with Abnar Tharn on 'The Userper Queen' quest after the Desert Winds Cavern part.
I hope this is the kind of feedback you are looking for and I can provide crash logs/reports later if that helps.
Magical1
Macbook Pro (13", 2017, 3.1Ghz i5, 8GB Ram, Intel Iris Plus Graphics 1.5 GB).
Mac OS X 10.13.6
Steam Package Version - 1555457005