Steps to reproduce:

1. Create some symlink to any directory and use it as persistent_dir parameter 
2. Create item with key like this log[/home/user/log.log,,,,,,,,/home/user/persistent_dir]

Result:
In the agent log you can find something like this: 

active check "log[/home/user/log.log,,,,,,,,/home/user/persistent_dir]" is not supported: file exists but is not a directory

Expected:
Working item