@Prabhu. Max Subfolder Level has nothing to do with the Sync files. It only relates to how deep the go when displaying the subfolders on the webpage. So, it is unrelated.
The errors you displayed earlier in your php error logs don’t related to Sync files either. The relate to displaying the listing as a paginated table. I will have to investigate that further, but it too does not relate to Sync files.
I am not sure I am understanding what is happening. Your 2 tests both completed without the error 1267 coming up. So, how often do you get this error and under what circumstance? Also, you should clear out your php logs, and then the next time you get the error, check your logs to see what PHP posted.
Could you verify what version of Advanced Folder Listing you have installed? Also your PHP version and MySQL version? Thanks.