View cache stopped working (CakePHP 2.8.9)

Hi

My app uses view caching intensively (whole page exept for a litte nocache-section). Unfortunatley this has stopped working for no obvious reason.

CacheAction is set probably, debug is 0 and the CacheHelper is included.

The cached view is written succesfully to /tmp/cache/views/ but CakePHP doesn’t load these cached files - the page is generated fully from scratch.

I know, this could be for any reason, but do you have a hint to start searching for solving this topic?

Thanks,
Frank