that was true for the first batch of FFL351a 3700K, but no longer true… FFL 351a and FFL350RD details in this thread
For me, FFL LEDs are a waste of time. They are still changing the phosphor recipe from one batch to the next. Some are very pink, some are neutral, and some have rather yellow tint w positive DUV.
The Fireflies CCT claims are also inconsistent… my recent FFL350RD 3500K actually measures 3883K… more detail in comments from Jackson here