On another Forge server setup all the node modules are owned by root:
forge@app-prod:/usr/lib/node_modules/npm/node_modules$ ll
total 1448
drwxr-xr-x 360 root root 12288 Oct 16 2020 ./
drwxr-xr-x 9 root root 4096 Oct 16 2020 ../
drwxr-xr-x 3 root root 4096 Oct 16 2020 JSONStream/
drwxr-xr-x 2 root root 4096 Oct 16 2020 abbrev/
drwxr-xr-x 2 root root 4096 Oct 16 2020 agent-base/
drwxr-xr-x 3 root root 4096 Oct 16 2020 agentkeepalive/
drwxr-xr-x 5 root root 4096 Oct 16 2020 ajv/
drwxr-xr-x 2 root root 4096 Oct 16 2020 ansi-align/
...
drwxr-xr-x 2 root root 4096 Oct 16 2020 write-file-atomic/
drwxr-xr-x 2 root root 4096 Oct 16 2020 xdg-basedir/
drwxr-xr-x 2 root root 4096 Oct 16 2020 xtend/
drwxr-xr-x 2 root root 4096 Oct 16 2020 y18n/
drwxr-xr-x 2 root root 4096 Oct 16 2020 yallist/
drwxr-xr-x 5 root root 4096 Oct 16 2020 yargs/
drwxr-xr-x 4 root root 4096 Oct 16 2020 yargs-parser/
so not sure yet if the staging server needs them all to be under root or forge.