Hi VT..first you shouldn't have repotted once bringing inside..Next I'd stop fertilizing till new growth in spring.
Whenever a plant is brought in from outside, some leaves can yellow, so it's normal, but if a plant is overpotted, (especially if overwatered) leaves will definately yellow.
According to The House Expert Plant book, Agaps do best when potbound, especially when trying to get to flower which happens in spring/summer.
Since you're in Vermont, keep semi-cool during winter months, but frost free.
Keep the soil dry for the most part..I dont know if you should underpot or if doing so will cause more stress. Good luck, Toni

Andrea, I just will agree with everything Hopeful has said....the yellowing leaves, if not too excess, can be normal. However sometimes we contribute to them yellowing by over...or under watering; too much light, a poor growing location...like putting it near a heat vent or near a door that is contantly being opened. Abrupt temperatures and air currents can cause the yellowing. If the loction allows too high a nighttime temeprature, that too can cause the yellowing.

You repotted the plant when it may have been quite happy being root-bound. Then again, how you re-sized the pot you put it into, may have cntributed to some stress.

Let it dry down between waterings, and don't feed it until it blooms.

I should have been more specific. I did put the plant into a pot the same size it had been growing in outdoors, knowing it likes to be potbound. I needed to put it in a plastic pot simply to lift it, but it didn't go up a size. I was guilty of overwatering it and now that it's drying out between waterings, I don't see as many yellowing leaves. How much sun do these guys like? I had it in the corner of my stairwell which is more a northeast exposure. Now that it's in a cranny of my kitchen, it's next to the patio slider and gets southeast light. However, most of the time it's cloudy during winter in Vermont.

Here in CA they are in every yard except mine. They are like a weed and love sun. The more sun the better. They will multiply in just a couple years to a huge clump. In a pot they may not be able to multiply that fast.

I agree with the bright light..In CA, I believe they can be kept in the garden yr round..is this true, Gobluedijm?
Or does it matter which part of Ca one lives in?
Either way, I'd underpot a bit if overpoted, keep soil on the dry side, withhold fertilizing, and keep in brightest light possible..They're pretty plants, but grows wide..Toni

Yeah they survive thru the winter. They might not in the mountains and snow areas. Anywhere where it doesn't freeze really bad they should be ok. We had frost here really bad last year and all around my neighborhood they are fine.
I had 1/4 inch ice in my little pond for a week.

I keep reading that Aggies love sun. However, is it too hot for them in Arizona sun. My aggies bloomed early spring but with yellowing leaves. They are not in a pot but in a flowerbed. As the temperatures reach 113F, the flowering has stopped and the leaves looked burned. Should they be potted or planted in the shade?