Auto redirect to root folder

I just found a way that can say "temporary fixed"

On .htaccess, Redirect Trailing Slashes:

I turn from 

Code:

RewriteBase /ci4/public/

# Redirect Trailing Slashes...
RewriteRule ^(.*)/$ /$1 [L,R=301]

to 

Code:

RewriteBase /ci4/public/

# Redirect Trailing Slashes...
RewriteRule ^(.*)/$ /ci4/public/$1 [L,R=301]

Then I move folders name "admin" form 'ci4/public/admin' (used for assets file)
to folders "ci4/public/assets/admin"

Then the problems has resolved. But I think this is not a best solution.

I wonder on .htaccess that I have RewriteBase is /ci4/public/, why redirect trailing slashes not redirect to this Base?