Login redirects to install.php

When logging in with SAML i’m redirected to the the following URL:

wp-content/plugins/saml-20-single-sign-on/saml/www/module.php/saml/sp/saml2-acs.php/1/wp-admin/install.php

which obviously doesn’t load. Logging in with the bypass url works fine.

I’ve got a quite complex server setup with both dedicated varnish and memcache servers. Memcache servers are being used as an object store with php and the PHP sessions are being held in the memcache servers.

Any idea why i’d be getting redirected to the install.php page?

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