eBay’s Duplicate Listings Policy states
“The duplicate listings policy is designed to help you list in a way that makes it easy for buyers to find and compare items that interest them.
You can’t have more than one fixed price listing of an identical item at the same time.
You can have more than one auction-style listing for identical items. However, only one duplicate auction-style listing without bids appears on eBay at a time. Separate listings may be created for the same item on different eBay sites, as long as the international shipping options don’t result in the listings cluttering the search results of any individual site.”
For full article, please see eBay’s Duplicate Listings Policy
At the same time, long time eBay sellers have reported duplicate listings getting created automatically due to eBay’s system glitches. Please see:
and there are many other such posts on eBay seller discussion forums.
So, how does Wonder Lister helps you?
In Wonder Lister, there is a system folder called “Potential Duplicates” which displays those active listings that APPEARS to be duplicate. You can look at each such listing to confirm if they really are duplicate and take appropriate action (may be End potentially duplicated listings). This would go a long way in ensuring that your account does not get suspended by eBay.