where are you.. big city name..

how intense is wind out there??

your media in that one pic looks bone dry ... can you keep the media .. and the plant properly moist...is not.. the leaves will start looking like yours do...

in one pic.. it looks like a couple crows are watching you in the window reflection.. whats that all about.. lol

water need thru the growing season can vary wildly.. perhaps you need to increase available water... i had to put dish washing trays under a couple of our plants.. to maintain proper water deep into the pot.. as the tomatoes got huge.. and the heat is peaking in august... and they look almost dead as it is...

they look the same.. but much worse than yours...

Id all the plant culture variables.. and then run thru them.. until you find which is the problem ...

ken

I also have this occuring to my table grapes vine that is about 3 years old. Are you sure that your vine is edible, as I tried to ID it and it comes up as Vitis davidii
Plant.

I have learned that the previous comment is correct about grapes not handling drought well. I am located in the USA zone 7.

All grapes, including V. davidii, are edible, even if not necessarily palatable. But OP bought a grafted grape, not a random seedling, so it should be a good variety. Symptoms look as if the plant got too hot and too dry. Water and shade from intense sun should help it recover. Grapes are not particularly drought sensitive, but any plant grown in a pot is vulnerable to too little water. In the ground grapes are fairly drought resistant.

Btw if, you identified your grape using an app there is no certaintly about the name. Many grapes have similar looking foliage. If it was sold as a table grape it should not be V. davidii.

Keep the upper inch of your pot soil loosened using a tableware fork, that will give water a better chance of evenly wetting.