I'm no expert, but I would not feed them past having a second deep filled for winter, and it's early for that. Cut them off and see what they do -- if the stores start to disappear with no real foraging activity, you are going to be stuck feeding them until a flow comes around, or winter gets here.
Bees are greedy, and will continue to draw wax and store syrup as long as you feed it. If they run out of room to store it, they will fill up the brood nest and swarm, too.
I fed my package this year up to a couple weeks ago to get enough comb drawn to overwinter them. Paritally full of syrup, but not capped, and I will leave them on their own until September. I did put a super of extracted frames on, as much to get the frames cleaned up as anything, but it's possible we will get soybean honey this year (couple thousand acres around me planted and growing well, unlike the last few years), so I want them to have the room. They are flying like crazy, so maybe they've found something.
I'm also feeding the small swarm I collected a couple weeks ago, I'll be feeding them up to October, likely. I believe I have a laying queen, so they will be getting a huge amount of syrup and protein patty if I want them full sized. I may leave them as a multistory nuc, though, depending on how fast they build up. May add some bees and brood in the next week or two as well, can't hurt once they are established. I've got them on some "superdeep" frames in 11.25" deep boxes, should be fun to see how they do. A big pain if I ever need to switch frames around, but so far they are drawing them out nicely on syrup and the frame of stores I swiped from another hive.