Local cache not fully purged
Cache::FileCache seems not able to have different cache_depth. When using default configuration, configuration is stored with
cache_depth=0 and sessions with
cache_depth=3. Probably depending on which request opens the cache,
cache_depth value is not respected: tokens and sessions are stored either with de 3-depth or a 0 one.
purgeLocalCache purges only 3-depth sessions. This can cause saturation of the
cache_depth (default is 3) or fix it to 3 for configuration.