Not sure what is happening to this sprout?

Hard to tell what’s going on with the blurple pics, but I would remove those bags and leave them off, your soil looks way to wet but hard to tell under the blurple light. Did you poke drainage holes in those cups? With the bags over them your holes are the only escape for mosture, and if you flooded those cups then bag them there is way to much moisture with nowhere for it to go and your seedling certainly cant drink it all up. More info would and pics under normal light and I could maybe help ya more. Cheers💨