Hi Simius! Could you insert the whole link, please? As I cannot open the link with my tablet you wrote. Thanks.
I still don't really get it, I could see why it would be that if it said het wijn but can't really when it is just wijn.
From the link posted in the comments here:
If no article at all comes before a het-word, then the adjective does not get the -e ending either.
If no article comes before a de-word, it does get the ending.