3.400 Genre filter not working properly

Hi,

I have a large movie collection and I noticed some of my movies had incorrect runtime tags so I then done a batch rescrape with the wizard and ticked runtime and the missing fanart option. After an hour or so Media Companion finished and all looked well.
It was only when I clicked on a Genre filter where I noticed the problem for example when I click on action it only filters 29 out of 4665 wheras I know I have a LOT more action movies then that. The only genre filter that does work is the custom filter I named "HD". I looked on these forums to see if anyone had experienced anything like it and found a thread that said something about using the wizard and ticking the 'rescrape media tags' option. This solution did work but only temporarily, the next time I opened the software the problem comes back. I have tried a fresh installation and the problem persists. I am running out of things to try here and I am not really comfortable with rescanning the whole database regularly as it is a major pain if something goes wrong. Any ideas?

I also forgot to mention all my movies are stored on internal hard drives so should always be availabe