Increasing `save_size` in texmf.cnf has no effect

Similarly to 161286, I have a "capacity exceeded (save size)" error for an auto-generated file with a large tree (forest package) which was automatically generated by a script.

I tried to increase the save_size in /etc/texmf/web2c/texmf.cnf which was the ouput of kpsewhich texmf.cnf, but the error persists (similar to 185153):

! TeX capacity exceeded, sorry [save size=80000].

Checking in all relevant configs yields:

$ for conf in $(kpsewhich --all texmf.cnf); do grep save_size "$conf"; done
save_size  = 200000
save_size  = 100000     % for saving values outside current group
save_size  = 100000     % for saving values outside current group

Question: Where can I change the save_size parameter?