Did you check to make sure the drip system is keeping everything evenely moist and not too wet or too dry? Start there of course!

I have this palm in my yard in Houston. My sprinkler turns on for only 2 minutes every other day. It is doing great and I have had it for almost 3 years.

Watering can be tricky as the negative effects of too much water can resemble too LITTLE water. Your palms are containerized right? Not sure how drip system works with smaller containerized plantings. Watering depends on a lot of factors (sun exposure and duration, soil type, heat, humidity, etc.) When you put your fingers beneath the soil to a half inch, how does it feel (wet, moist, dry)? Keep in mind that this species is native to humid tropical/subtropical, fairly moist climates (not a desert or Mediterranean species at all). Good luck!