I had a cutting that was doing wonderfully and had substantial root growth around the clear plastic cup, so I transplanted it to a larger pot, started adjusting it to light (2 days shade, 2 days partial light, then full sunlight) and it has lost its 3 leaves and has not grown or done anything in 2 weeks now. I don't know what to do. Leave it indoors or outdoors? Fertilize it, or not?

Its current state:

Hold out hope, I have had several this season that did nothing for about 2 months then they grew all of the sudden.

some of them play w our heads, leave it alone as is...I's put an upsided down cup/ bottle without bottom (use lid at night) with venting holes over it for semi humidity...

I had few do the same thing,
increase the humidity as Grasa suggested,
keep the soil from drying out completely
It will sulk for a few weeks to a month then go on and grow.

As long as it's green there's hope.

Patience. Two days isn't even close to enough time to acclimate to full sun. Give it a week of indirect light, or maybe 2, then some filtered light for a week or two, and then a little less filter, so do on. If you do not have active growth, you need TLC, not transition. You have done the hard work of getting the cutting, getting it rooted. Being in a hurry can waste all of that.

Kruzerci

Quoting from you.../ - (2 days shade, 2 days partial light, then full sunlight)..

The underlined statement has a LOT to do with what happened. At this age and so fragile shoots/leaves, full sunlight is a way too much for a fig. Leaves are the first to be capable, once stronger, to take direct radiation from the sun....then,  much later the little buds..
If I have a baby tree which I MUST have  with a strong development in that particular season for whatever reason, it will go the the sun at the right time and always prepare various tin foil cap style shields, to fix over the buds to keep them protected from direct exposure. It works quite well. The little plant grows faster in view of the more energy it gets from the sun,  without cooking the shoots and additional growth.
I managed to 'up-green' the fig leaves to a healthy marked color once they are strong enough to take sun, by adding small doses of fish meal to these figs, 2 table spoons monthly for 1 gal pot
This is what I normally do


Francisco

this weekend, rest of my cuttings in the cup will be moved to 1 gal pots. once done, they will go outside under the front porch. that location gets few hours of sun in the morning and late afternoon. it will be partail sun since it will be filtered by the rail on side and front along with good size japanese maple.

tender leaves on the cutting will get bleached and will fall off if you leave them in full sun for too long.