Hey NVL,
i had same issues yesterday i saw your post about this and saw you using HD Mesh 3.
I have that one too completly, so what i did open custome scenery and opend my scenery_packs.ini file.
What i did there, to simple test a few things i just disabled the HD Mesh 3 like this.
SCENERY_PACK_DISABLED Custom Scenery/zzz_HDMESH_zzz/
As you can see i just put _DISABLED behind the SCENERY_PACK.
So there is no need to deinstall the whole Mesh.
My results about the change i didn't had any error again after i disabled it!
Surely i can't give guarantee that it works for you too or if it is really that problem, but you might wanna try it!
Greetings and clear skies!