Lachlann isnt there in "Sorrow Among Stones"

Currently doint the "Sorrow Among Stones" Quest,
ive defeated both bosses - and than my next task was "put Lachlan to rest" but he isnt there. I also cannot enter the memorial Gates. So iam basicallly completly stuck and cannot proceed.

https://gyazo.com/59582fffa8e66ab6e3b6fa06d968e5ee

As an addition to me previews post:
The gates are open - but iam unable to pass trough them.

I was now able to pass trough the memorial Gates - but i cannot trigger Lachlan to become a zombie. iam forced to stay next to him and cant talk to him or anything

https://gyazo.com/9c19fe25a7f93646f8054c1da7aaee41

Hi,

I triggered the "Sorow among stones" quest. Lachlann walked through the memorial gate, I decided to go to town to sell a few items. When I returned, Lachlann was in from of the large tombstone, but I cannot trigger him to turn into a zombie. He keeps saying "Are you numb in the head, there is much to do". I cannot move further down the questline.

In fact, I have two quest lines : 1) The mysterial share : Search for the count's grave pas the memorial gate and 2) Sorrow among stones : follow Lacnhalnn".

Cheers!

Same thing just happened to me. Did you ever figure out how to move on?