File Delays With FTP Delivery - Adobe Data Warehouse

As of late, we have had files arriving later than we have specified in our Data Warehouse schedule. For example, we have several reports scheduled at the same time to arrive to our FTP server, but some reports arrive hours later.

Is this a known issue or is there something we can do to mitigate this issue? This is making our reporting less reliable than ideal as not all reports arrive on time and we are unsure why