Although I haven't grown papilios indoors I grow many outside. (see photo below) What you may do is gently lift up on the bulb to see if the roots are rotted off. This species does best with very good drainage, I have one mounted on a board as like a staghorn fern. It does like regular water, again with good drainage. They will always shed their leaves when the roots are disturbed.
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I have the same problem. I put it in dormancy the same time as all my other Amaryllis bulbs and it is the only one that won't wake up. Although I think I broke one of the green tip when it was waking up. I planted in on top of the soil in a flower pot. I have gently shook the bulb and look like the root are good. I will try lift it up to check on the root tomorrow.

H. papilio is not like the hybrids you buy; it is an evergreen. Don't try to put it into dormancy. It will naturally slow down growth in the heat of late summer and cold of mid-winter, but it never stops growing. It's fairly hardy. For northern folks, try a sunny window in winter. Also, I fertilize mine quite a bit using water soluble, high phosphate and minors, adding ag epsom.

When I remove the seed pods from the scapes, I will plant them out in the flower bed myself. I belive outside weater should be beneficial for them.