how do i remove specific LODs?

so uh i updated tectonic (one of my world gen mods) and it has a few bugs in the terrain - and now distant horizons shows incorrect terrain - like straigh cliffs and when i get there its a completely different terrain. now i removed the chunks with mce selector and downgraded tectonic but thares still this issue - i guess it because the lod chunks stayed the same. how do i fix that?