kletskater on "[Plugin: Wordfence Security] falcepos or problem"?"

scanresult gives
File contains suspected malware URL: /home/deb52593/domains/mydomain.nl/public_html/wp-content/w3tc/dbcache/8a3/790/476/8a3790476157e60394601009d9e91d52.php
Filename: wp-content/w3tc/dbcache/8a3/790/476/8a3790476157e60394601009d9e91d52.php
Bad URL: http://aa.bb/
File type: Not a core, theme or plugin file.
Issue first detected: 26 mins ago.
Severity: Critical
Status New
after delete the file, next time it is there again.
Is this a falcepossitive or a problem?

http://wordpress.org/extend/plugins/wordfence/