They are still quite pale, but I don't see how they can get proper colour while buried deep under such a dense foliage.

You wouldn't guess there were any berries here at all if you were just passing by :)

Hi all! Had a mystery plant pop up in the spring that now has dark purple berry clusters all over.
Hard to discern one plant from another so there may be multiple growing together here. Berries are roughly pea-sized with a variety of thorns on a super flexible vine with teardrop/heart shaped leaves with deep vertical veins.
Thanks in advance for your help!