Also, when an eBay import is performed, we try to match the eBay listings with existing items so dupes aren’t created. We do this by first looking at the Custom Label on eBay to see if it matches an existing SKU in SixBit (assuming Custom Label is mapped to SKU in the SixBit Options|Refreshes).
If not, then we try to match on Product ID and if not that, then finally by looking at identical titles.
If they were not matched, my best guess is that the Custom Label on eBay isn’t unique or isn’t filled in and mapped to the SKU field in SixBit.