Even this site suffers from disconnections on the rare occasion during imports.
Additional checks are put into place to insert a partial datapoint record if it fails to retrieve the full hero data which means experience calculations should continue to work as normal.
Unfortunately, we've already processed thousands of heroes which means some profiles may or may not be already missing some hero records (I think it's rare for this to happen in any case)
This explains why we occasionally have certain players jumping up the time trial ladders as the next import suddenly places a new high paragon character to be calculated instantly. I'll be manually fixing this if I spot any more.