URP 'Transparency Sort Mode' problem with vertex position shader graph

So, I have this shader to animate 2D trees which kind of works, except for the fact that some trees get sorted by vertical transparency making them animate uncontrollably as seen in the video below:

If I set the vertical sorting to zero, it works perfectly, but I need the sorting active:


Do you have any suggestions in order to solve this issue?
Thanks.

 

Please, let me know if I wasn't clear with the problem's description.

Thank you.