Thanks @stanofh. Put up little fan on. But still trying to figure out what causing leaves to burn out. Any lychee expert out there who can chime in?

It is possible the light could be too intense, if the lamps are too close. I have read some people say too much blue light can cause leaf burn.

It looks to me like there might be a hormonal issue with the plant, causing it to leaf out faster than the plant can adequately sustain, but any number of different things could be causing that.

I also suspect the roots system may not be very established. If that is the case you need to keep the plant warm and moist and turn down the light intensity until the plant has a chance to root out more. Or it could possibly be salt burn.

I ended up taking it out and put it back with new soil. I did notice that roots were not as spread out as i thought it would since i had it in the new pot for about 8 months now.

i have several seedlings. mine have done that too. i have one doing it now, and i think its a couple of things...

1 - too much water. they seem to like constant soil moisture. not to wet or too dry. and too wet seems to impede nutrient uptake. i think this is why ive heard many lyche growers say mulch is important.

2 - Lychee seem to need live soil. - worm castings , compost tea , mycorrhizal fungi...

3 - sometimes they try to put out more new leaves than the plants can handle. the roots have to bring up minerals, water etc... not enough nitrogen, or other mineral can cause it, but if there are not enough roots, adding chemicals will just make it worse... so, what i do is prune 1/2 of the new growth off. it takes the demand off the roots and lets them provide all the nutrients to just a few leaves... this has actually helped me.

I think my problem was too much water and maybe fertilizer. Since I re-potted it, i do see some new buds coming, but not sure how it will do. I will try to add some mulch this week. Thank you and everyone else for replying.

In the winter lychee shouldn't don't need much water and certainly no fertilizer. I have two they're very healthy but I'm still waiting for a winter with enough chill hours for get fruit.