ErrorDocument and Header always set ... env=

Hi,

I'd like to short-circuit certain requests that contain no session
cookie with a HTTP 403, an ErrorDocument and a few response headers.

The following almost works:

RewriteCond %{REQUEST_METHOD} !OPTIONS
RewriteCond %{HTTP_COOKIE} !session=
RewriteRule ^/foo - [E=FOO:FOO,R=403,L]

Header always set X-Foo "test1" env=FOO
Header always set X-Bar "test2"

ErrorDocument 403 /error403.json

However, if the ErrorDocument is used, only X-Bar gets set but not
X-Foo. Without an ErrorDocument, both X-Foo and X-Bar get set (when
the RewriteCond and -Rule all match). The documentation for
mod_headers would lead me to believe that the "always" would be
sufficient to also set X-Foo.  Does anyone here have suggestions how
to get this whole construct to work, or alternatives to achieve the
same effect?

We're currently using httpd 2.4.58 on Ubuntu.

Rainer

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