The problem is very nicely described here. If there is a symbolic link to a
directory, such that the original and link are at a different depth in the
filesystem, org-mode latex preview fails.

The bug and how to reproduce (a potential solution to it) can be found here:
https://lists.gnu.org/archive/html/bug-gnu-emacs/2023-10/msg01152.html

Copy of the most relevant part:

>* How to reproduce:*
>
>* 1. Run `mkdir -p ~/a_dir/org'.*
>
>* 2. Run `ln -s ~/a_dir/org ~/docs'.*
>
>* 3. Run `emacs -Q ~/docs/example.org <http://example.org>'.*
>
>* 4. Insert into the file "$2+2=4$", press `C-c C-x C-l', and see that it*
>* does not work.*
>
>* 5. Kill emacs.*
>
>* 6. Run `emacs -Q ~/a_dir/org/example.org <http://example.org>'.*
>
>* 7. Insert into the file "$2+2=4$, press `C-c C-x C-l', and see LaTeX*
>* preview.*

The link describes that one should use file-truename before
file-relative-name. Ergo one possible solution could be adding
file-relativename to a bunch of places, or if org-mode is hardwired to
produce the files into /tmp, maybe relative paths should not be used (as
far as I can tell, the error occurs when it tries to read
../../../tmp/orgtexRANDOM... which is actually /tmp/orgtexRANDOM...)


-- 
Emil Vatai