File not found for minified & cached files

We use W3TC for minifying and caching. In the error-log of apache2 I see the following entries. The strange thing is that the extensions at the end even do look like JavaScript statements

– {href}
– ‘+c+’
– ‘+this.escapeHTML(a)+’

How can we fix this? What might be the root-cause for it?

Regards
Flo

### Logs
Jun 19 16:43:52 jenny httpd-XXXXX: [Fri Jun 19 16:43:21 2015] [error] [client XX.XX.XX.XX] File does not exist: /home/admin/sites/XXXXX/production/current/wp-content/cache/minify/000000/{href}, referer: https://XXXXX/wp-content/cache/minify/000000/pY5BDsIwDAQ_1OAe-FDSLG0gjiPbBfF71AOqQOqp15nVaEfi4kI3jYyX6IM4hx5nhLSWmqFUS9qYLaI-SYZRNIMb3W1zRr2uc2k2jGdKP_yb2vUTLYtSEnFzjf1w8Xdm976AMVxpEmY0D4pe3xcu7QM.js
Jun 19 16:43:52 jenny httpd-XXXXX: [Fri Jun 19 16:43:21 2015] [error] [client XX.XX.XX.XX] File does not exist: /home/admin/sites/XXXXX/production/current/wp-content/cache/minify/000000/’+c+’, referer: https://XXXXXX/wp-content/cache/minify/000000/pY5BDsIwDAQ_1OAe-FDSLG0gjiPbBfF71AOqQOqp15nVaEfi4kI3jYyX6IM4hx5nhLSWmqFUS9qYLaI-SYZRNIMb3W1zRr2uc2k2jGdKP_yb2vUTLYtSEnFzjf1w8Xdm976AMVxpEmY0D4pe3xcu7QM.js
Jun 19 23:46:32 jenny httpd-XXXXX: [Fri Jun 19 23:46:01 2015] [error] [client 180.76.15.148] File does not exist: /home/admin/sites/XXXXXX/production/current/wp-content/cache/minify/000000/’+this.escapeHTML(a)+’

https://www.ads-software.com/plugins/w3-total-cache/