antua

I copy files to override catalog and it clean itself after a few days and all content turn to default. Before that happens all overrides are working fine. I put there: frontcontroller, categorycontroller, orderhistory, etc. Whole files with some modifications. If I purge cache nothing bad is happening. In beginning I thought that happens when automatic update occurs but it happens even without updates. File permissions for folders 755 and 644 for files. I do not know where to search for a problem solution. Prestashop 1.6.1.7 Thank you for help!