I can't say for certain as it tweaks quite a few settings but I can tell you that whatever the setting its tweaking doing skyrim launcher and then hitting ultra (vanilla settings) does not undo the problem. I had to use BethIni to completely default them to get the precache grass to work.
I have also noticed that shadow quality gets messed up (I think related to how its changing and accounting for decals) and I have to adjust it via launcher settings. If I don't get I get very ugly shadows (showing on character arms as dark blotches very obvious when you start game with Alternative Start). I found a thread on here via reddit that pointed to nexus forum where they discuss the settings etc (if you wanted to investigate it further).
Very weird to me that BethIni causes my game various issues I have to adjust via skyrim launcher or manually to correct (by that I mean I use BethIni Ultra settings, then I have to go into Skyrim launcher to adjust certain values its setting to medium or low THEN I go back into BethIni to manually tweak the fields that skyrim launcher ultra settings do not do as well). It's pretty annoying and I am sure not everything is set optimally with all this jumping back and forth.
I have RTX 4090 and Intell 13900 so I throwing everything at my computer max settings and discovering this (been modding for years but limited in what i could do until now).
No Grass In Object - Page 89 - File topics - The Nexus Forums (nexusmods.com)