Customer sometime report there was a surge in the number of files sent by Data Feeds. For example, a customer usually get 10 files for a single day. Suddenly, they start receiving 100s of files for a single day.
Generally, this is due to settings for Late Arriving Hits were turned on recently. It would appear to the customer that the normal amount of data for the affected hour/day arrived as usual, but the extra large amount of data sent by data feeds was for previous hours and dates.
For the report suite that have had late hits turned on already for more than 24 hours, the first feed request after it is turned on will do a 24 hour backfill of export files.