Hard to see the entire tree, but it does not look like black tip to me. Just looks like the ends of a few new claws are discolored. If it bothers you, I would clip the black end of of the little new claw. ( Just the end of the claw.. nothing else) Can't see the inside of the other...

But it doesn't look like anything I would be to concerned about as of yet. Black tip is when the entire stem starts to turn black and continues on down or it starts at a particular point on the stem

Make sure the cool air isn't blowing right on the tree.. It loves the warmth, so keep it in the sun if you can.

How old is it? It's rooted I take? Looks like you have nice leaves and it looks like it is doing well..

I think you are alright. If it continues to get worse, then I would raise an eyebrow.. Not now!!! ;-)

Remember, wet/dry..

Take care,

Laura