Exactly the same on my driver seat, looking for some pro tip for this, but not to be found here i think.
When i gently put a finger inside (haha) i can feel that the outer fabric is glued to the foam, or to a thinner "in between fabric"
The solution to fix this, instead of buying a now seat or expensive pro replacement, i think is to cut a piece of stronger fabric made for furniture/chairs and similar. One pice of fabric as said, bigger then the crack, put it on the inside, then i would use textile glue and strectch it inwards and let it dry. On the outside i would also do the same, but with more finesse to make it look better. Well, i dont think it will be good looking, but to choose of the ugly or when the foam pops out...and the seating MUST be replaced.
I will do this in my T6 to slow down the seat from total ruin, and of course i have to buy a proper seat cover. I will post some pics of this when im done, this is very usual problem on this vans.
Have a good one!