DTV R15-100 Recordings skipping ahead

For about the last two months we've noticed a number of the old recordings skip ahead.  We recorded those that we could and deleted the old ones that skipped.  However, now the newer recordings are also skipping ahead.  Resetting the 8yr old DTV R15-100 has not helped.  Is there any way to correct the current recordings so they will no longer skip ahead and stop this from happening again?