Different return windows?

Spoonie_Turtle

Just out of idle curiosity really.  I bought three items from one seller at the end of November, two of which say returns accepted until Dec 23rd and one says the returns window closed on Dec 7th.  Business seller, all items of exactly the same type just different pattern on each listing, bought together and arrived in one parcel as expected.

The only reason I noticed is checking on the one I had to return (which still has Dec 23rd as the return deadline).  I don't know if anyone else had encountered this or had it themselves on their own items?