Both vessels are 1,5 L water with 11 % sugar and 3 table spoon loose tea leaves. While the vessel on the left is green Darjeeling, the one on the right is regular black Darjeeling. Both vessels were initially shaken once. Only the one on the right is creating a liquid phase. Does anybody know why?

Going with a guess here: the green one looks cloudy; maybe colloidal or other material present in the green but not in the black tea helps bring the sugar into solution. But could be simply the vessel shape.
It would be neat to repeat the experiment swapping the vessels.

The vessel shapes are nearly identical, it's most certainly related to composition of the teas

This reminds me of a tea recipe I found a while ago with the separation as an intentional effect: https://lemmy.dbzer0.com/post/48900321