Are you sure that is a Triangle Palm (Dypsis). It kinda looks like a Hyophorbe (Spindle species). But I have confused these two in the past, so you may be right. You have provided no zonal information. Florida is a BIG state with a lot of variation in the winter between the north and the south. How cold has it gotten by you? (Triangles are more cold hardy than Spindles, btw.) What is the soil like? Has rain been decent? If the palm came from a lowlight environment and then went out into full sun, that can bleach the older leaves. Otherwise, I am clueless on this one.

I live in central Florida on the east coast. I'm not 100%sure it's a triangle palm, it just looks alot like others I've seen that I know are triangle palms. I bought it a yr ago when it was much smaller. It has been chilly, but y no means cold. The coldest day so far was like mid 40's in the morning. Soil is the usual Florida sandy mix, I did add some potting soil when I planted it. Rain has been fine, it gets watered twice a week and has been in full sun since it's been planted

Definitely a Hyophorbe verschaffeltii (Spindle palm)⦠they always look yellowy, but that is excessively yellow⦠They do NOT like cold (though mid-40s is not super cold⦠certainly colder than they prefer, though). And maybe a bit lacking in nitrogen. May also not be used to sun yet.

They are SUPER SENSITIVE TO SUN if not acclimated to it. Yes, I know they can grow in full sun, but if it went from a shaded position to sun, it most definitely is sun burned. Should grow out of it. I overwinter mine in the basement under lights, when I move them outside, they are first in full shade for a couple of weeks. Other palms also will burn if not acclimated first, but these are really bad for rapid transitions to full sun. Been there, done that,

Hyophorbes are NOT cold tolerant at all. They also sun burn very readily if not acclimated. Otherwise, they are EASY and are not bad house palm selections...even in the North.

I hope your palm gets out of its funk. Perhaps MiracleGro at half strength will help. DO resist the urge to heavily fertilize. That would likely kill your Palm.