[TYPO3-dev] caching error with pageCacheToExternalFiles = true

[Chris]

Hello list,

we recently had a caching problem on a website (Typo3 v. 4.2.6)

In the install tool we use the option [FE][pageCacheToExternalFiles] = true

The cache_pages table has reached 16 Go and we lost most of the FE 
output : pages were blank  with a caching error in the source code from 
tslib_fe :

<!-- CACHING ERROR, sorry -->
<!-- Cached page generated 23-04-09 18:08. Expires 23-04-09 18:33 -->
<!-- Parsetime: 476 ms-->

we tried by clearing all caches via the backend but the error was still 
here, we had to truncate the cache_pages table in order to regenerate a 
correct FE output

in typo3temp/cache_pages/, files and rights are OK

we are still investigating but any help would be appreciated

cheers,

Chris