Listings ending although duration is set to "Good 'Til Cancelled"

[sloths_treasures]

Recently, I noticed that many of my listings ended.  When I realized that I had a huge amount of listings in my Unsold section, I relisted everything.  In my haste, I did not consider that many of those listings included variations.  So on a daily basis I have to refund buyers for items that were previously sold via listings with variations.  

Can someone from eBay explain why these listings ended without my initiation?  Can you also explain how I can prevent this in the future?

[dbfolks166mt]

     The following link should help explain to you why the listings were ended.

https://www.ebay.com/help/selling/listings/creating-managing-listings/relisting-items?id=4147 

     As for the unsold issue the view has a number of options/settings one of them being All Statuses that includes not only the unsold items but the sold ones as well. Strange contradiction in terms but I go into that view on occasion and delete the items that have been sold.