Symfony route collision with folder in /web - php

Question

So, when defining a route in symfony (3) like this:
app:
path: /app
defaults:
_controller: WebsiteBundle:App:index
And there happens to be a folder named app (containing assets like JS, images, etc.) inside your web folder this route stops working in a production environment. It just redirects to /web/app/ and then throws a 404. When serving through the console on localhost this works fine since all routing happens in PHP by magix, but when using apache this seems to go wrong.
I think these two lines /web/.htaccess are breaking everything, but I'm not sure. I'm not a master of .htaccess and I always copy-paste the magic I find online (or provided by the default symfony build).
RewriteCond %{ENV:REDIRECT_STATUS} ^$
RewriteRule ^app\.php(?:/(.*)|$) %{ENV:BASE}/$1 [R=301,L]
In this particular case I could solve it by just running the /app route on / instead, but for future reference an answer to this riddle might come in handy.
Thanks in advance, y'all crazy smart people out there.
[UPDATE]
This is the full .htaccess file in the apache root directory:
#php_value memory_limit 512M
#php_value upload_max_filesize 20M
#php_value post_max_size 20M
<IfModule mod_rewrite.c>
RewriteEngine On
#Force HTTPS
# RewriteEngine On
# RewriteCond %{HTTPS} off
# RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
# Determine the RewriteBase automatically and set it as environment variable.
# If you are using Apache aliases to do mass virtual hosting or installed the
# project in a subdirectory, the base path will be prepended to allow proper
# resolution of the app.php file and to redirect to the correct URI. It will
# work in environments without path prefix as well, providing a safe, one-size
# fits all solution. But as you do not need it in this case, you can comment
# the following 2 lines to eliminate the overhead.
RewriteCond %{REQUEST_URI}::$1 ^(/.+)/(.*)::\2$
RewriteRule ^(.*) - [E=BASE:%1]
# Rewrite all queries to the web directory.
RewriteRule ^(.*)$ %{ENV:BASE}web/$1 [L]
# Rules to correctly serve gzip compressed CSS and JS files.
# Requires both mod_rewrite and mod_headers to be enabled.
<IfModule mod_headers.c>
# Serve gzip compressed CSS files if they exist and the client accepts gzip.
RewriteCond %{HTTP:Accept-encoding} gzip
RewriteCond %{REQUEST_FILENAME}\.gz -s
RewriteRule ^(.*)\.css $1\.css\.gz [QSA]
# Serve gzip compressed JS files if they exist and the client accepts gzip.
RewriteCond %{HTTP:Accept-encoding} gzip
RewriteCond %{REQUEST_FILENAME}\.gz -s
RewriteRule ^(.*)\.js $1\.js\.gz [QSA]
# Serve correct content types, and prevent mod_deflate double gzip.
RewriteRule \.css\.gz$ - [T=text/css,E=no-gzip:1]
RewriteRule \.js\.gz$ - [T=text/javascript,E=no-gzip:1]
RewriteRule \.woff\.gz$ - [T=application/x-font-woff,E=no-gzip:1]
<FilesMatch "(\.js\.gz|\.css\.gz)$">
# Serve correct encoding type.
Header set Content-Encoding gzip
# Force proxies to cache gzipped & non-gzipped css/js files separately.
Header append Vary Accept-Encoding
</FilesMatch>
</IfModule>
</IfModule>
and this is the full .htaccess file in the symfony web folder:
# Use the front controller as index file. It serves as a fallback solution when
# every other rewrite/redirect fails (e.g. in an aliased environment without
# mod_rewrite). Additionally, this reduces the matching process for the
# start page (path "/") because otherwise Apache will apply the rewriting rules
# to each configured DirectoryIndex file (e.g. index.php, index.html, index.pl).
DirectoryIndex app.php
# By default, Apache does not evaluate symbolic links if you did not enable this
# feature in your server configuration. Uncomment the following line if you
# install assets as symlinks or if you experience problems related to symlinks
# when compiling LESS/Sass/CoffeScript assets.
# Options FollowSymlinks
# Disabling MultiViews prevents unwanted negotiation, e.g. "/app" should not resolve
# to the front controller "/app.php" but be rewritten to "/app.php/app".
<IfModule mod_negotiation.c>
Options -MultiViews
</IfModule>
<IfModule mod_rewrite.c>
RewriteEngine On
# Determine the RewriteBase automatically and set it as environment variable.
# If you are using Apache aliases to do mass virtual hosting or installed the
# project in a subdirectory, the base path will be prepended to allow proper
# resolution of the app.php file and to redirect to the correct URI. It will
# work in environments without path prefix as well, providing a safe, one-size
# fits all solution. But as you do not need it in this case, you can comment
# the following 2 lines to eliminate the overhead.
RewriteCond %{REQUEST_URI}::$1 ^(/.+)/(.*)::\2$
RewriteRule ^(.*) - [E=BASE:%1]
# Sets the HTTP_AUTHORIZATION header removed by Apache
RewriteCond %{HTTP:Authorization} .
RewriteRule ^ - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
# Redirect to URI without front controller to prevent duplicate content
# (with and without `/app.php`). Only do this redirect on the initial
# rewrite by Apache and not on subsequent cycles. Otherwise we would get an
# endless redirect loop (request -> rewrite to front controller ->
# redirect -> request -> ...).
# So in case you get a "too many redirects" error or you always get redirected
# to the start page because your Apache does not expose the REDIRECT_STATUS
# environment variable, you have 2 choices:
# - disable this feature by commenting the following 2 lines or
# - use Apache >= 2.3.9 and replace all L flags by END flags and remove the
# following RewriteCond (best solution)
RewriteCond %{ENV:REDIRECT_STATUS} ^$
RewriteRule ^app\.php(?:/(.*)|$) %{ENV:BASE}/$1 [R=301,L]
# If the requested filename exists, simply serve it.
# We only want to let Apache serve files and not directories.
RewriteCond %{REQUEST_FILENAME} -f
RewriteRule ^ - [L]
# Rewrite all other queries to the front controller.
RewriteRule ^ %{ENV:BASE}/app.php [L]
</IfModule>
<IfModule !mod_rewrite.c>
<IfModule mod_alias.c>
# When mod_rewrite is not available, we instruct a temporary redirect of
# the start page to the front controller explicitly so that the website
# and the generated links can still be used.
RedirectMatch 302 ^/$ /app.php/
# RedirectTemp cannot be used instead
</IfModule>
</IfModule>